Update italic highlighting rules to avoid intra word highlights. ajax…

…org#4358

lib/ace/mode/markdown_highlight_rules.js

@@ -148,7 +148,7 @@ var MarkdownHighlightRules = function() {
             regex : "([*]{2}|[_]{2}(?=\\S))(.*?\\S[*_]*)(\\1)"
         }, { // emphasis * _
             token : "string.emphasis",
-            regex : "([*]|[_](?=\\S))(.*?\\S[*_]*)(\\1)"
+            regex : "(?<=\\s|^)([*_])[^*_]*\\1(?=\\s|$)"
         }, { //
             token : ["text", "url", "text"],
             regex : "(<)("+