Improve guard so it works for no eof new line

ftplugin/crystal.vim

@@ -1,4 +1,5 @@
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'crystal') == -1
+
 if exists('b:did_ftplugin')
   finish
 endif
@@ -79,4 +80,5 @@ let &cpo = s:save_cpo
 unlet s:save_cpo
 
 " vim: nowrap sw=2 sts=2 ts=8:
+
 endif