runtime(zsh,sh): set and unset compiler in ftplugin

closes: #15699

Signed-off-by: Konfekt <Konfekt@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/zsh.vim b/runtime/ftplugin/zsh.vim
index aee8900..5e69336 100644
--- a/runtime/ftplugin/zsh.vim
+++ b/runtime/ftplugin/zsh.vim
@@ -2,7 +2,7 @@
 " Language:             Zsh shell script
 " Maintainer:           Christian Brabandt <cb@256bit.org>
 " Previous Maintainer:  Nikolai Weibull <now@bitwi.se>
-" Latest Revision:      2024 May 06 by Vim Project (MANPAGER=)
+" Latest Revision:      2024 Sep 19
 " License:              Vim (see :h license)
 " Repository:           https://github.com/chrisbra/vim-zsh
 
@@ -26,11 +26,13 @@
   else
     command! -buffer -nargs=1 ZshKeywordPrg echo system('MANPAGER= zsh -c "autoload -Uz run-help; run-help <args> 2>/dev/null"')
   endif
+  setlocal keywordprg=:ZshKeywordPrg
+  let b:undo_ftplugin .= '| setl keywordprg< | sil! delc -buffer ZshKeywordPrg'
+
   if !exists('current_compiler')
     compiler zsh
   endif
-  setlocal keywordprg=:ZshKeywordPrg
-  let b:undo_ftplugin .= 'keywordprg< | sil! delc -buffer ZshKeywordPrg'
+  let b:undo_ftplugin .= ' | compiler make'
 endif
 
 let b:match_words = '\<if\>:\<elif\>:\<else\>:\<fi\>'