small fix to Changelog format

ChangeLog

@@ -1,7 +1,9 @@
 version <unreleased>
 
+Extractors
 + [egghead:course] Add support for egghead.io courses
 
+
 version 2017.01.08
 
 Core
@@ -18,6 +20,7 @@ Extractors
 * [comedycentral/mtv] Add support for HLS videos (#11600)
 * [discoverygo] Fix JSON data parsing (#11219, #11522)
 
+
 version 2017.01.05
 
 Extractors