docs/extension-point: add code block languages

Change-Id: Id160fd67424a24f1aa9074ed1eb2216d0403cfc9
diff --git a/src/main/resources/Documentation/extension-point.md b/src/main/resources/Documentation/extension-point.md
index 83e7e45..dc757ba 100644
--- a/src/main/resources/Documentation/extension-point.md
+++ b/src/main/resources/Documentation/extension-point.md
@@ -15,7 +15,7 @@
 
 Example:
 
-```
+```ini
 [gerrit]
   installModule = com.googlesource.gerrit.plugins.replication.ReplicationExtensionPointModule
 ```
@@ -34,7 +34,7 @@
 
   Example:
 
-  ```
+  ```java
   DynamicItem.bind(binder(), ReplicationPushFilter.class).to(ReplicationPushFilterImpl.class);
   ```
 
@@ -48,6 +48,6 @@
 
   Example:
 
-  ```
+  ```java
   DynamicItem.bind(binder(), AdminApiFactory.class).to(AdminApiFactoryImpl.class);
   ```