[clang-tidy] adjust scripts to subsubsections in Release Notes
I added subsubsections for typical Clang-tidy entries in Release Notes, so now scripts are aware of this changes.
I don't have GitHub commit access, so please commit changes.
Reviewers: aaron.ballman, alexfh, hokein
Reviewed By: alexfh
Subscribers: njames93, xazax.hun, cfe-commits
Tags: #clang-tools-extra, #clang
Differential Revision: https://reviews.llvm.org/D72527