[clang-tidy] rename_check.py misc-string-constructor bugprone-string-constructor

Summary:
Rename misc-string-constructor to bugprone-string-constructor +
manually update the lenght of '==='s in the doc file.

Reviewers: hokein, xazax.hun

Reviewed By: hokein, xazax.hun

Subscribers: mgorny, xazax.hun, cfe-commits

Differential Revision: https://reviews.llvm.org/D40388

llvm-svn: 318916