patch 9.1.0583: filetype: *.pdf_tex files are not recognized

Problem:  filetype: *.pdf_tex files are not recognized
Solution: Detect '*.pdf_tex' files as tex filetype
          (Jonas Dujava)

Those files are generated by inkscape, when exporting, see e.g.
https://inkscape.org/doc/inkscape-man.html

closes: #15250

Signed-off-by: Jonas Dujava <jonas.dujava@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index 07ed129..0cd9cfb 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -2455,6 +2455,9 @@
 " Sometime we need to view its content for debugging
 au BufNewFile,BufRead *.{pgf,nlo,nls,thm,eps_tex,pygtex,pygstyle,clo,aux,brf,ind,lof,loe,nav,vrb,ins,tikz,bbx,cbx,beamer}	setf tex
 
+" LaTeX files generated by Inkscape
+au BufNewFile,BufRead *.pdf_tex			setf tex
+
 " ConTeXt
 au BufNewFile,BufRead *.mkii,*.mkiv,*.mkvi,*.mkxl,*.mklx   setf context
 
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index a410785..24388b9 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -764,7 +764,7 @@
     teraterm: ['file.ttl'],
     terminfo: ['file.ti'],
     'terraform-vars': ['file.tfvars'],
-    tex: ['file.latex', 'file.sty', 'file.dtx', 'file.ltx', 'file.bbl', 'any/.texlive/texmf-config/tex/latex/file/file.cfg', 'file.pgf', 'file.nlo', 'file.nls', 'file.thm', 'file.eps_tex', 'file.pygtex', 'file.pygstyle', 'file.clo', 'file.aux', 'file.brf', 'file.ind', 'file.lof', 'file.loe', 'file.nav', 'file.vrb', 'file.ins', 'file.tikz', 'file.bbx', 'file.cbx', 'file.beamer'],
+    tex: ['file.latex', 'file.sty', 'file.dtx', 'file.ltx', 'file.bbl', 'any/.texlive/texmf-config/tex/latex/file/file.cfg', 'file.pgf', 'file.nlo', 'file.nls', 'file.thm', 'file.eps_tex', 'file.pygtex', 'file.pygstyle', 'file.clo', 'file.aux', 'file.brf', 'file.ind', 'file.lof', 'file.loe', 'file.nav', 'file.vrb', 'file.ins', 'file.tikz', 'file.bbx', 'file.cbx', 'file.beamer', 'file.pdf_tex'],
     texinfo: ['file.texinfo', 'file.texi', 'file.txi'],
     texmf: ['texmf.cnf'],
     text: ['file.text', 'file.txt', 'README', 'LICENSE', 'COPYING', 'AUTHORS', '/usr/share/doc/bash-completion/AUTHORS', '/etc/apt/apt.conf.d/README', '/etc/Muttrc.d/README'],
diff --git a/src/version.c b/src/version.c
index ab317d3..6633b7b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    583,
+/**/
     582,
 /**/
     581,