[clang-tools-extra] [clang-tidy]bugprone-unused-return-value ignore `++` and `--` operator overloading (PR #84922)

[Piotr Zegar via cfe-commits]

https://github.com/PiotrZSL approved this pull request.

Overall change is fine.
There is only one usage of isOperatorOverloading, so you could consider changing this into:
isOverloadAssigmentOperator and put all those operator kinds in a matcher instead of messing with SmallVector.

https://github.com/llvm/llvm-project/pull/84922