[gen_keycodes] Clarify the README that the code scheme also applies to physical keys (#106078)
[gen_keycodes] Clarify the README that the code scheme also applies to physical keys (#106078)

* Impl

* Revert some changes

* More doc changes

* Remove legacy code
tvolkert/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter