vim:autocmd: Match current word only if it exists

Check that the current word under the cursor exists (not empty) before
adding it as match.

Fix the disappearing of the welcome screen after a short time when
opening vim without file as argument.

.config/vim/vimrc.d/80-autocommands.vim

@@ -52,8 +52,13 @@ augroup termdebug_bindings
 augroup END
 
 " Highlight word under cursor
+function! HighlightCurrentWord()
+	if (expand('<cword>') != '')
+		exec 'match CursorColumn /\V\<' . escape(expand('<cword>'), '/\') . '\>/'
+	endif
+endfunction
 augroup highlight_current_word
 	au!
-	au CursorHold * :exec 'match CursorColumn /\V\<' . escape(expand('<cword>'), '/\') . '\>/'
-	au CursorMoved * :exec 'match'
+	au CursorHold * call HighlightCurrentWord()
+	au CursorMoved * match
 augroup END