As part of the migration to a common strategy/method for branching and releasing across
the main angular repositories, updates need to be made to the documentation. These changes
reflect the updates made and is based on the following document which describes the
merging label expectations: https://docs.google.com/document/d/197kVillDwx-RZtSVOBtPb4BBIAw0E9RT3q3v6DZkykU
PR Close#38401
Joey Perrott
Jason Aden
Miško Hevery
Trotyl Yu