Improve guard so it works for no eof new line

ftplugin/rust/tagbar.vim

@@ -1,4 +1,5 @@
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'rust') == -1
+
 "
 " Support for Tagbar -- https://github.com/majutsushi/tagbar
 "
@@ -39,4 +40,5 @@ unlet s:save_cpo
 
 
 " vim: set et sw=4 sts=4 ts=8:
+
 endif