lib/ignore: Revert comma handling, upgrade globbing package

This was fixed upstream due to our ticket, so we no longer need the
manual handling of commas. Keep the tests and better debug output around
though.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3081

vendor/manifest

@@ -40,7 +40,7 @@
 		{
 			"importpath": "github.com/gobwas/glob",
 			"repository": "https://github.com/gobwas/glob",
-			"revision": "d877f6352135181470c40c73ebb81aefa22115fa",
+			"revision": "82e8d7da03805cde651f981f9702a4b4d8cf58eb",
 			"branch": "master"
 		},
 		{