[clang-tidy] Fix example provided by add_new_check.py

Currently test for newly added check in clang-tidy fails,
this is because Fix is attached to note, but test is executed
without --fix-notes. This change adding --fix-notes to test.

Fixes: https://github.com/llvm/llvm-project/issues/50400

Reviewed By: carlosgalvezp

Differential Revision: https://reviews.llvm.org/D146875