[documentation] Updated info for element registration

Description:
  Updated documentaion for custom element registration
  monkey patch.
[documentation] Updated info for element registration

Description:
  Updated documentaion for custom element registration
  monkey patch.
Merge branch 'master' of https://github.com/Nevraeka/WebComponentsMonkeyPatch
Merge pull request #2 from Nevraeka/master

[documentation] Updated info for element registration