1. Links to the programming chapter were broken after 69c74f850e. They're now fixed with a redirect in readthedocs.io, but this commit updates them to the latest URL.
2. Most docs links should point to "stable" instead of "latest", since most users will want the docs for the released version, not the upcoming version. The exceptions are the programming chapter, and instructions for building the Python bindings from source.
PiperOrigin-RevId: 502821526
Change-Id: If0a55ab2be4751ba0165bf644030464234083133
Up the mujoco bindings version to 2.1.2.post2.
Keep the capsule deconstructor which calls mj_freeContext, because mjr_freeContext is idempotent.
PiperOrigin-RevId: 435714183
Change-Id: I9f8615f85f2b3e383f447f6684e61200039d57d4