Ensure strings with colons are matched as strings

With thanks to @cbandy.

Co-Authored-By: Chris Bandy <[email protected]>

Author: ralish

after/syntax/yaml.vim

@@ -40,7 +40,7 @@ syn keyword yamlConstant NULL Null null NONE None none NIL Nil nil
 syn keyword yamlConstant TRUE True true YES Yes yes ON On on
 syn keyword yamlConstant FALSE False false NO No no OFF Off off
 
-syn match  yamlKey	"^\s*\zs[^ \t\"#]\+\ze\s*:"
+syn match  yamlKey	"^\s*\zs[^ \t\"\'#]\+\ze\s*:"
  syn match  yamlKey	"^\s*-\s*\zs[^ \t\"\'#]\+\ze\s*:"
 syn match  yamlAnchor	"&\S\+"
 syn match  yamlAlias	"*\S\+"