The main interface documentation hasn't been updated substantially
since 2017 and is missing notes for many of its current features and
requirements.
Also change the recommendation for implementors from BasePlayer to
SimpleBasePlayer to ensure new classes are more likely to cover all
of the interface requirements.
#minor-release
PiperOrigin-RevId: 534027117
(cherry picked from commit 6de6bd9c4f23b87427b7d2c4cb2c330aef5fba49)
3704c7fc8d