refactor code duplication

browser/lib/convertModeName.js

@@ -0,0 +1,14 @@
+export default function convertModeName (name) {
+  switch (name) {
+    case 'ejs':
+      return 'Embedded Javascript'
+    case 'html_ruby':
+      return 'Embedded Ruby'
+    case 'objectivec':
+      return 'Objective C'
+    case 'text':
+      return 'Plain Text'
+    default:
+      return name
+  }
+}