fix: Correctly tokenize YAML meta tags with non alphabetical characte…

…rs after multiline string (#4706)

* fix: Correctly tokenize YAML meta tags with non alphabetical characters after multiline string
* prevent backtracking and spaces in meta tags

lib/ace/mode/_test/text_yaml.txt

@@ -23,6 +23,7 @@ bill-to:  &id001
     street: |
             123 Tornado Alley
             Suite 16
+    ref-id: id123  
     city:   East Centerville
     state:  KS
 

lib/ace/mode/_test/tokens_yaml.json

@@ -122,7 +122,12 @@
 ],[
    "start",
   ["indent","    "],
-  ["meta.tag","city"],
+  ["meta.tag","ref-id"],
+  ["keyword",":"],
+  ["text","   id123"]
+],[
+   "start",
+  ["meta.tag","    city"],
   ["keyword",":"],
   ["text","   East Centerville"]
 ],[

lib/ace/mode/yaml_highlight_rules.js

@@ -57,10 +57,10 @@ var YamlHighlightRules = function() {
                 regex: "[&\\*][a-zA-Z0-9-_]+"
             }, {
                 token: ["meta.tag", "keyword"],
-                regex: /^(\s*\w.*?)(:(?=\s|$))/
+                regex: /^(\s*\w[^\s:]*?)(:(?=\s|$))/
             },{
                 token: ["meta.tag", "keyword"],
-                regex: /(\w+?)(\s*:(?=\s|$))/
+                regex: /(\w[^\s:]*?)(\s*:(?=\s|$))/
             }, {
                 token : "keyword.operator",
                 regex : "<<\\w*:\\w*"