Add repo-links for default channels

This commit adds comments with links to source repositories of default channels.

Author: deathaxe

Package Control.sublime-settings

@@ -6,8 +6,10 @@
 		// channel_v4 for python 3.8 compatible libraries to enable plugins
 		// to migrate to python 3.8 until packagecontrol.io supports new scheme.
 		// Note: Must always be located before default channel in the list!
+		// Repo: https://github.com/packagecontrol/channel
 		"https://packagecontrol.github.io/channel/channel_v4.json",
 		// default channel for packages
+		// Repo: https://github.com/wbond/package_control_channel
 		"https://packagecontrol.io/channel_v3.json"
 	],