mergestate: document mergestate records in an organized way
This makes clear which mergestate record is used for what and group them based
on how they are used right now.
Differential Revision: https://phab.mercurial-scm.org/D8719
mergestate: remove unused unsupported related mergestate records
I tried to find users of this but was unable to find. Seems like RECORD_OVERRIDE
is doing for what they were used before.
Differential Revision: https://phab.mercurial-scm.org/D8718
mergestate: add comments about couple of record types and minor reorder
I am trying to divide the records into certain groups and then have dedicated
objects for them. Taking baby steps in that direction.
Differential Revision: https://phab.mercurial-scm.org/D8717