[clang] [clang] Implement __builtin_stdc_rotate_left, __builtin_stdc_rotate_right (PR #160259)

[NagaChaitanya Vellanki via cfe-commits]

chaitanyav wrote:

@erichkeane, the compiler is issuing a warning. I will use a better example
```
test_doc_example.cpp:4:38: warning: implicit conversion from 'unsigned int' to 'unsigned _BitInt(17)' changes value from 3504544 to 96672
      [-Wconstant-conversion]
    4 |   unsigned _BitInt(17) rotated_odd = __builtin_stdc_rotate_left(0x1ABCD, 5);
      |                        ~~~~~~~~~~~   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

https://github.com/llvm/llvm-project/pull/160259