(#3834) - Follow up, highlight code snippets

docs/_posts/2015-08-03-pouchdb-4.0.0-ballast-overboard.md

@@ -19,7 +19,9 @@ We previously used `bluebird` as our `Promise` polyfill in node.js because it is
 
 PouchDB will always use the globally available `Promise` object where available, so if you have only used standard `Promise` functionality, this change will not break anything. If you require the extra functionality provided by `bluebird`, then you can have PouchDB use it with
 
-    global.Promise = require('bluebird');
+```js
+global.Promise = require('bluebird');
+````
 
 * Remove `local_seq` - ([#4080](https://github.com/pouchdb/pouchdb/issues/4080))
 
@@ -29,26 +31,34 @@ This was a little-used functionality whose semantics are due to change in CouchD
 
 These callbacks have long been replaced with the `EventEmitter`-style `changes()`, `replicate()` and `sync()` APIs, and are finally being removed. If you still have:
 
-    db.changes({
-      onChange: changeFun,
-      complete: completeFun
-    });
+```js
+db.changes({
+  onChange: changeFun,
+  complete: completeFun
+});
+```
 
 You can replace them with:
 
-    db.changes()
-      .on('change', changeFun)
-      .on('complete', completeFun);
+```js
+db.changes()
+  .on('change', changeFun)
+  .on('complete', completeFun);
+```
 
 * Remove `uptodate` event - ([#4100](https://github.com/pouchdb/pouchdb/issues/4100))
 
 `uptodate` was an event introduced to indicate when a `live` replication had finished processing all current changes and was waiting on future changes. It has since been replaced by the `paused` event, which will do the same and additionally indicate whether the replication was paused due to an error. If you have:
 
-    replication.on('uptodate', doneFun);
+```js
+replication.on('uptodate', doneFun);
+```
 
 You can replace it with:
 
-    replication.on('paused', doneFun);
+```js
+replication.on('paused', doneFun);
+```
 
 ### New features