Add graphqlTemplateString to jsExpression cluster

For pangloss/vim-javascript, we need to add graphqlTemplateString to the
jsExpression cluster. This fixes comment-based syntax tagging when this
JavaScript plugin is used.

Author: jparise

after/syntax/javascript/graphql.vim

@@ -48,7 +48,7 @@ if graphql#has_syntax_group('jsTemplateExpression')
   hi def link graphqlTaggedTemplate jsTaggedTemplate
   hi def link graphqlTemplateExpression jsTemplateExpression
 
-  syn cluster jsExpression add=graphqlTaggedTemplate
+  syn cluster jsExpression add=graphqlTemplateString,graphqlTaggedTemplate
   syn cluster graphqlTaggedTemplate add=graphqlTemplateString
 elseif graphql#has_syntax_group('javaScriptStringT')
   " runtime/syntax/javascript.vim