Fix mime type for vue

Use text/x-vue.

Change-Id: I4c42b41113d09732164474dea4a87a8bd55b0779
diff --git a/web/element/language.ts b/web/element/language.ts
index ef882cf..d26b034 100644
--- a/web/element/language.ts
+++ b/web/element/language.ts
@@ -357,7 +357,7 @@
       return StreamLanguage.define(vhdl);
     case 'text/velocity':
       return StreamLanguage.define(velocity);
-    case 'text/vue':
+    case 'text/x-vue':
       return vue();
     case 'text/x-webidl':
       return StreamLanguage.define(webIDL);