Merge pull request #18534 from neovim/backport-18480-to-release-0.7

[Backport release-0.7] fix(runtime/genvimvim): omit s[ubstitute] from vimCommand

runtime/syntax/vim.vim

@@ -120,9 +120,6 @@ else
  com! -nargs=*	VimFoldt	<args>
 endif
 
-" commands not picked up by the generator (due to non-standard format) {{{2
-syn keyword vimCommand contained	py3
-
 " Deprecated variable options {{{2
 if exists("g:vim_minlines")
  let g:vimsyn_minlines= g:vim_minlines

scripts/genvimvim.lua

@@ -44,12 +44,13 @@ local function cmd_kw(prev_cmd, cmd)
 end
 
 -- Exclude these from the vimCommand keyword list, they are handled specially
--- in syntax/vim.vim (vimAugroupKey, vimAutoCmd). #9327
-local function is_autocmd_cmd(cmd)
+-- in syntax/vim.vim (vimAugroupKey, vimAutoCmd, vimSubst). #9327
+local function is_special_cased_cmd(cmd)
   return (cmd == 'augroup'
           or cmd == 'autocmd'
           or cmd == 'doautocmd'
-          or cmd == 'doautoall')
+          or cmd == 'doautoall'
+          or cmd == 'substitute')
 end
 
 local vimcmd_start = 'syn keyword vimCommand contained '
@@ -60,7 +61,7 @@ for _, cmd_desc in ipairs(ex_cmds.cmds) do
     w('\n' .. vimcmd_start)
   end
   local cmd = cmd_desc.command
-  if cmd:match('%w') and cmd ~= 'z' and not is_autocmd_cmd(cmd) then
+  if cmd:match('%w') and cmd ~= 'z' and not is_special_cased_cmd(cmd) then
     w(' ' .. cmd_kw(prev_cmd, cmd))
   end
   prev_cmd = cmd