runtime(vim): Update base-syntax, improve :import highlighting

- Match "autoload" as a keyword in :import commands.
- Match an expression argument for the filename.

closes: #15375

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index debed2b..d0f3202 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -2,7 +2,7 @@
 " Language:	   Vim script
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
-" Last Change:	   2025 May 16
+" Last Change:	   2025 May 17
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -34,7 +34,7 @@
 " regular vim commands {{{2
 " GEN_SYN_VIM: vimCommand normal, START_STR='syn keyword vimCommand contained', END_STR='nextgroup=vimBang'
 syn keyword vimCommand contained abo[veleft] al[l] ar[gs] arga[dd] argd[elete] argdo argded[upe] arge[dit] argg[lobal] argl[ocal] argu[ment] as[cii] b[uffer] bN[ext] ba[ll] bad[d] balt bd[elete] bel[owright] bf[irst] bl[ast] bm[odified] bn[ext] bo[tright] bp[revious] br[ewind] brea[k] breaka[dd] breakd[el] breakl[ist] bro[wse] buffers bufd[o] bun[load] bw[ipeout] c[hange] cN[ext] cNf[ile] cabo[ve] cad[dbuffer] cadde[xpr] caddf[ile] caf[ter] cb[uffer] cbe[fore] cbel[ow] cbo[ttom] cc ccl[ose] cd cdo ce[nter] cex[pr] cf[ile] cfd[o] cfir[st] cg[etfile] cgetb[uffer] cgete[xpr] chd[ir] changes che[ckpath] checkt[ime] chi[story] cl[ist] cla[st] clo[se] cle[arjumps] cn[ext] cnew[er] cnf[ile] co[py] col[der] colo[rscheme] com[mand] comc[lear] comp[iler] con[tinue] conf[irm] nextgroup=vimBang
-syn keyword vimCommand contained cons[t] cope[n] cp[revious] cpf[ile] cq[uit] cr[ewind] cs[cope] cst[ag] cw[indow] d[elete] delm[arks] deb[ug] defc[ompile] defe[r] delf[unction] di[splay] dif[fupdate] diffg[et] diffo[ff] diffp[atch] diffpu[t] diffs[plit] difft[his] dig[raphs] disa[ssemble] dj[ump] dli[st] dr[op] ds[earch] dsp[lit] e[dit] ea[rlier] em[enu] endfo[r] endt[ry] endw[hile] ene[w] ev[al] ex exi[t] exu[sage] f[ile] files filet[ype] fin[d] fina[lly] fini[sh] fir[st] fix[del] fo[ld] foldc[lose] foldd[oopen] folddoc[losed] foldo[pen] g[lobal] go[to] gu[i] gv[im] h[elp] helpc[lose] helpf[ind] helpt[ags] ha[rdcopy] hi[ghlight] hid[e] his[tory] hor[izontal] ij[ump] il[ist] imp[ort] int[ro] ip[ut] is[earch] isp[lit] j[oin] ju[mps] k kee[pmarks] keepj[umps] keepp[atterns] nextgroup=vimBang
+syn keyword vimCommand contained cons[t] cope[n] cp[revious] cpf[ile] cq[uit] cr[ewind] cs[cope] cst[ag] cw[indow] d[elete] delm[arks] deb[ug] defc[ompile] defe[r] delf[unction] di[splay] dif[fupdate] diffg[et] diffo[ff] diffp[atch] diffpu[t] diffs[plit] difft[his] dig[raphs] disa[ssemble] dj[ump] dli[st] dr[op] ds[earch] dsp[lit] e[dit] ea[rlier] em[enu] endfo[r] endt[ry] endw[hile] ene[w] ev[al] ex exi[t] exu[sage] f[ile] files filet[ype] fin[d] fina[lly] fini[sh] fir[st] fix[del] fo[ld] foldc[lose] foldd[oopen] folddoc[losed] foldo[pen] g[lobal] go[to] gu[i] gv[im] h[elp] helpc[lose] helpf[ind] helpt[ags] ha[rdcopy] hi[ghlight] hid[e] his[tory] hor[izontal] ij[ump] il[ist] int[ro] ip[ut] is[earch] isp[lit] j[oin] ju[mps] k kee[pmarks] keepj[umps] keepp[atterns] nextgroup=vimBang
 syn keyword vimCommand contained keepa[lt] l[ist] lN[ext] lNf[ile] la[st] lab[ove] lan[guage] lad[dexpr] laddb[uffer] laddf[ile] laf[ter] lat[er] lb[uffer] lbe[fore] lbel[ow] lbo[ttom] lc[d] lch[dir] lcl[ose] lcs[cope] ld[o] le[ft] lefta[bove] lex[pr] leg[acy] lf[ile] lfd[o] lfir[st] lg[etfile] lgetb[uffer] lgete[xpr] lgr[ep] lgrepa[dd] lhi[story] ll lla[st] lli[st] lmak[e] lne[xt] lnew[er] lnf[ile] lo[adview] loc[kmarks] lockv[ar] lol[der] lop[en] lp[revious] lpf[ile] lr[ewind] lt[ag] lw[indow] ls m[ove] ma[rk] marks menut[ranslate] mes[sages] mk[exrc] mks[ession] mksp[ell] mkv[imrc] mkvie[w] mod[e] n[ext] nb[key] nbc[lose] nbs[tart] noa[utocmd] noh[lsearch] nos[wapfile] nu[mber] o[pen] ol[dfiles] on[ly] opt[ions] ow[nsyntax] p[rint] pa[ckadd] packl[oadall] pb[uffer] nextgroup=vimBang
 syn keyword vimCommand contained pc[lose] ped[it] po[p] pp[op] pre[serve] prev[ious] pro[mptfind] promptr[epl] prof[ile] profd[el] ps[earch] pt[ag] ptN[ext] ptf[irst] ptj[ump] ptl[ast] ptn[ext] ptp[revious] ptr[ewind] pts[elect] pu[t] pw[d] q[uit] quita[ll] qa[ll] r[ead] rec[over] red[o] redr[aw] redraws[tatus] redrawt[abline] redrawtabp[anel] reg[isters] res[ize] ret[ab] rew[ind] ri[ght] rightb[elow] ru[ntime] rub[y] rubyd[o] rubyf[ile] rund[o] rv[iminfo] sN[ext] sa[rgument] sal[l] san[dbox] sav[eas] sb[uffer] sbN[ext] sba[ll] sbf[irst] sbl[ast] sbm[odified] sbn[ext] sbp[revious] sbr[ewind] scr[iptnames] scripte[ncoding] scriptv[ersion] scs[cope] setf[iletype] sf[ind] sfir[st] sh[ell] sim[alt] sig[n] sil[ent] sla[st] sn[ext] so[urce] sp[lit] spe[llgood] spelld[ump] nextgroup=vimBang
 syn keyword vimCommand contained spelli[nfo] spellr[epall] spellra[re] spellu[ndo] spellw[rong] spr[evious] sre[wind] st[op] sta[g] star[tinsert] startg[replace] startr[eplace] stopi[nsert] stj[ump] sts[elect] sun[hide] sus[pend] sv[iew] sw[apname] synti[me] sync[bind] smi[le] t tN[ext] ta[g] tags tab tabc[lose] tabd[o] tabe[dit] tabf[ind] tabfir[st] tabm[ove] tabl[ast] tabn[ext] tabnew tabo[nly] tabp[revious] tabN[ext] tabr[ewind] tabs tc[d] tch[dir] te[aroff] ter[minal] tf[irst] tj[ump] tl[ast] tn[ext] to[pleft] tp[revious] tr[ewind] try ts[elect] u[ndo] undoj[oin] undol[ist] unh[ide] unlo[ckvar] uns[ilent] up[date] v[global] ve[rsion] verb[ose] vert[ical] vi[sual] vie[w] vim9[cmd] viu[sage] vne[w] vs[plit] w[rite] wN[ext] wa[ll] wi[nsize] winc[md] wind[o] winp[os] nextgroup=vimBang
@@ -286,7 +286,7 @@
 syn case match
 
 " All vimCommands are contained by vimIsCommand. {{{2
-syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutocmd,vimAugroup,vimBehave,vimCall,vimCatch,vimConst,vimDoautocmd,vimDebuggreedy,vimDef,vimDefFold,vimDelcommand,@vimEcho,vimElse,vimEnddef,vimEndfunction,vimEndif,vimExecute,vimIsCommand,vimExtCmd,vimExFilter,vimFor,vimFunction,vimFuncFold,vimGrep,vimGrepAdd,vimGlobal,vimHelpgrep,vimHighlight,vimLet,vimLoadkeymap,vimLockvar,vimMake,vimMap,vimMark,vimMatch,vimNotFunc,vimNormal,vimRedir,vimSet,vimSleep,vimSort,vimSyntax,vimThrow,vimUnlet,vimUnlockvar,vimUnmap,vimUserCmd,vimVimgrep,vimVimgrepadd,vimMenu,vimMenutranslate,@vim9CmdList,@vimExUserCmdList,vimLua,vimMzScheme,vimPerl,vimPython,vimPython3,vimPythonX,vimRuby,vimTcl
+syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutocmd,vimAugroup,vimBehave,vimCall,vimCatch,vimConst,vimDoautocmd,vimDebuggreedy,vimDef,vimDefFold,vimDelcommand,@vimEcho,vimElse,vimEnddef,vimEndfunction,vimEndif,vimExecute,vimIsCommand,vimExtCmd,vimExFilter,vimFor,vimFunction,vimFuncFold,vimGrep,vimGrepAdd,vimGlobal,vimHelpgrep,vimHighlight,vimImport,vimLet,vimLoadkeymap,vimLockvar,vimMake,vimMap,vimMark,vimMatch,vimNotFunc,vimNormal,vimRedir,vimSet,vimSleep,vimSort,vimSyntax,vimThrow,vimUnlet,vimUnlockvar,vimUnmap,vimUserCmd,vimVimgrep,vimVimgrepadd,vimMenu,vimMenutranslate,@vim9CmdList,@vimExUserCmdList,vimLua,vimMzScheme,vimPerl,vimPython,vimPython3,vimPythonX,vimRuby,vimTcl
 syn cluster vim9CmdList	contains=vim9Abstract,vim9Class,vim9Const,vim9Enum,vim9Export,vim9Final,vim9For,vim9Interface,vim9Type,vim9Var
 syn match vimCmdSep	"\\\@1<!|"	skipwhite nextgroup=@vimCmdList,vimSubst1,vimFunc
 syn match vimCmdSep	":\+"	skipwhite nextgroup=@vimCmdList,vimSubst1
@@ -373,6 +373,47 @@
 syn keyword vimFTCmd    contained	filet[ype]
 syn keyword vimFTOption contained	detect indent off on plugin
 
+" Import {{{2
+" ======
+syn keyword	vimImportAutoload	contained	autoload	skipwhite nextgroup=vimImportFilename
+if s:vim9script
+  syn region	vimImportFilename contained
+        \ start="\S"
+        \ skip=+\%#=1
+          "\ continuation operators at SOL
+          \\n\%(\s*#.*\n\)*\s*\%([[:punct:]]\+\&[^#"'(]\)
+            \\|
+          "\ continuation operators at EOL
+          \\%(\%([[:punct:]]\+\&[^#"')]\)\s*\%(#.*\)\=\)\@<=$
+            \\|
+          \\n\%(\s*#.*\n\)*\s*as\s
+            \\|
+          \\%(^\s*#.*\)\@<=$
+            \\|
+          \\n\s*\\\|\n\s*#\\ 
+        \+
+        \ matchgroup=vimCommand
+        \ end="\s\+\zsas\ze\s\+\h"
+        \ matchgroup=NONE
+        \ end="$"
+        \ skipwhite nextgroup=vimImportName
+        \ contains=@vim9Continue,@vimExprList,vim9Comment
+        \ transparent
+else
+  syn region	vimImportFilename contained
+        \ start="\S"
+        \ skip=+\n\s*\\\|\n\s*"\\ +
+        \ matchgroup=vimCommand
+        \ end="\s\+\zsas\ze\s\+\h"
+        \ matchgroup=NONE
+        \ end="$"
+        \ skipwhite nextgroup=vimImportName
+        \ contains=@vimContinue,@vimExprList
+        \ transparent
+endif
+syn match	vimImportName	contained	"\%(\<as\s\+\)\@<=\h\w*\>"	skipwhite nextgroup=@vimComment
+syn match	vimImport		"\<imp\%[ort]\>"		skipwhite nextgroup=vimImportAutoload,vimImportFilename
+
 " Augroup : vimAugroupError removed because long augroups caused sync'ing problems. {{{2
 " ======= : Trade-off: Increasing synclines with slower editing vs augroup END error checking.
 syn cluster vimAugroupList	contains=@vimCmdList,vimFilter,vimFunc,vimLineComment,vimSpecFile,vimOper,vimNumber,vimOperParen,@vimComment,vimString,vimSubst,vimRegister,vimCmplxRepeat,vimNotation,vimCtrlChar,vimContinue
@@ -1941,7 +1982,7 @@
 endif
 exe "syn sync maxlines=".s:vimsyn_maxlines
 syn sync linecont	"^\s\+\\"
-syn sync linebreaks=1
+syn sync linebreaks=2
 syn sync match vimAugroupSyncA	groupthere NONE	"\<aug\%[roup]\>\s\+[eE][nN][dD]"
 
 " ====================
@@ -2074,6 +2115,9 @@
  hi def link vimHiStartStop	vimHiTerm
  hi def link vimHiTerm	Type
  hi def link vimHLGroup	vimGroup
+ hi def link vimImport	vimCommand
+ hi def link vimImportAutoload	Special
+ hi def link vimImportAs	vimImport
  hi def link vimInsert	vimString
  hi def link vim9KeymapLineComment	vimKeymapLineComment
  hi def link vimKeymapLineComment	vimComment