Fix syntax highlighting for javascript files

Change-Id: I66d97573e4f4d6bd4707ba17ccadd77e19dd5dc9

gerrit-gwtui/src/main/java/net/codemirror/mode/mode_map

diff --git a/gerrit-gwtui/src/main/java/net/codemirror/mode/mode_map b/gerrit-gwtui/src/main/java/net/codemirror/mode/mode_map
index bcb615a..e448fa9 100644
--- a/gerrit-gwtui/src/main/java/net/codemirror/mode/mode_map
+++ b/gerrit-gwtui/src/main/java/net/codemirror/mode/mode_map
@@ -51,4 +51,5 @@
 text/xml
 application/xml
 
+application/x-javascript = application/javascript
 text/x-java-source = text/x-java