[clang-tidy][docs] Note MISRA/AUTOSAR checks are not accepted (#214661)

Checks that directly reference MISRA/AUTOSAR are not accepted for
legal/license reasons. Generic overlapping checks without such links
remain fine.

Fixes #160940

GitOrigin-RevId: 371f0426f9d0c865a87321b24b0e0e349c52102f