Provide platform compatibility option in API documentation

[vittorioromeo]

I couldn't find a part of the documentation which explicitly mentions what APIs are supported for a given platform. For example, how do I know if SDL_GetClipboardText is supported on Emscripten?

It would be nice to have some sort of table at the end of every function-specific documentation page, e.g.:

Android	Emscripten	FreeBSD	Haiku OS	iOS	Linux	macOS	NetBSD	Nintendo Switch	Nintendo 3DS	OpenBSD	PlayStation 2	PlayStation 4	PlayStation 5	PlayStation Portable	PlayStation Vita	RISC OS	SteamOS	tvOS	Windows	Windows GDK	Xbox
✔️	✔️	❌	❌	✔️	✔️	❌	✔️	✔️	✔️	❌	✔️	✔️	✔️	❌	✔️	✔️	✔️	❌	✔️	✔️	✔️

[slouken]

You should assume every API is available and always check for errors. Even if an API may not be supported now, it's likely to be added in a future version and users might drop in a new SDL library with fixes and improved support.

[vittorioromeo]

You should assume every API is available and always check for errors

#9834 and #9819 would go a long way in helping!