[Request] Native menu bars

[LIJI32]

Since SDL3 seems to be getting a lot of great new OS integration APIs such as SDL_ShowOpenFileDialog, I'd like to request a native menu bar API. Menu bars are useful and important for simple desktop games (a-la Solitaire, Minesweeper, SkiFree) and applications (e.g. emulators) alike. Additionally, manually adding such functionality into SDL projects requires a lot of OS-specific code, and it breaks window sizing functions, so having this built directly into SDL itself would be very nice.