small fix syntax highlighting in vue.js files (#11706)

* small fix syntax highlighting in vue.js files

* changes after review by mikedavis

runtime/queries/vue/highlights.scm

@@ -6,9 +6,13 @@
 
 (attribute
   (attribute_name) @attribute
-  (quoted_attribute_value
+  [(attribute_value) (quoted_attribute_value)]? @string)
-    (attribute_value) @string)
+ 
-)
+(directive_attribute
+  (directive_name) @attribute
+  (directive_argument)? @attribute
+  (directive_modifiers)? @attribute
+  [(attribute_value) (quoted_attribute_value)]? @string) 
 
 (comment) @comment
 
@@ -18,4 +22,7 @@
   "</"
   "{{"
   "}}"
-] @punctuation.bracket
+  "/>" 
+] @punctuation.bracket
+"=" @punctuation.delimiter
+