Auto update Last change in vim help files

plugin/autocmds.vim

@@ -8,6 +8,9 @@ augroup benieAugroup
   " Highlight conflict markers in any filetype
   au FileType * call matchadd('Todo', '^\(<<<<<<<\||||||||\|=======\|>>>>>>>\)\s\ze.*$')
 
+  " Update `Last change: <date>` on write then jump back previous position
+  au BufWritePost *.txt 1s/Last change: \zs.*$/\=strftime('%Y %b %d')/e|norm!``
+
   " Read template into buffer then send line 1 to the black hold register
   au BufNewFile todo.md read ~/.vim/templates/skeleton.todo.md | 1delete _
   " Attempt to expand snippet named `_template` if it exists