create_join_table uses same logic as HABTM reflections

Before this change, create_join_table would not remove the common prefix
in the join table name, unlike ActiveRecord::Reflections. A HABTM
between Music::Artist and Music::Record would use a table
music_artists_records, while create_join table would create
music_artists_music_records.
small refactors to actionview renderers
marking private methods which dont work if called on their own anyways
adding missing test coverage
Fixed typo in comment
Merge pull request #16219 from skanev/fix-create-join-table-with-common-prefix

Make create_join_table use the same logic as HABTM reflections
Merge pull request #16227 from Aguynamedsteve/typo_correction

Fixed typo in comment [ci skip]
Merge pull request #16224 from egilburg/renderer_refactors

Some ActionView renderer refactors