remove custom messages for deprecated/removed options

[na-na-hi]

This warning system isn't used in any meaningful way and the messages are pointless when DOCS/interface-changes.rst has more detailed and helpful information, so just remove them and tell users to see DOCS/interface-changes.rst instead.

[github-actions[bot]]

Download the artifacts for this pull request:

Windows

• mpv-i686-w64-mingw32
• mpv-x86_64-w64-mingw32
• mpv-x86_64-windows-msvc

macOS

• mpv-macos-12-intel
• mpv-macos-13-intel
• mpv-macos-14-arm

[Dudemanguy]

I think the buck passed on this.