Support upper-case SCRIPT tags in htmlmixed mode

mode/htmlmixed/htmlmixed.js

@@ -30,6 +30,7 @@ CodeMirror.defineMode("htmlmixed", function(config, parserConfig) {
 
   function html(stream, state) {
     var tagName = state.htmlState.tagName;
+    if (tagName) tagName = tagName.toLowerCase();
     var style = htmlMode.token(stream, state.htmlState);
     if (tagName == "script" && /\btag\b/.test(style) && stream.current() == ">") {
       // Script block: mode to change to depends on type attribute