[clang-tidy] rename_check.py: maintain alphabetical order in Renamed checks section

Summary:
Also use //check// in add_new_check.py for terminology consistency.

PS

My GitHub ID is [[ https://github.com/EugeneZelenko | EugeneZelenko ]], if it's necessary for attribution.

Reviewers: alexfh, hokein, aaron.ballman, njames93, MyDeveloperDay

Reviewed By: njames93

Subscribers: Andi, xazax.hun, cfe-commits

Tags: #clang-tools-extra, #clang

Differential Revision: https://reviews.llvm.org/D73580