[clang-tools-extra] [clang-tidy] Redirect hicpp-ignored-remove-result to bugprone-unused-return-value (PR #184547)

[via cfe-commits]

IamYJLee wrote:

> At least we should say that here is algorithms passed to option `CheckedFunctions` is limited to only 3 functions

> We should say that `AllowCastToVoid` is set to `true` by default (unlike in main check which has `false`)

@vbvictor 
Adding something to `hicpp/ignored-remove-result.rst` might not be appropriate, since it redirects to `bugprone/unused-return-value.rst`.  
It has already been added to `bugprone/unused-return-value.rst`, so that should be enough.

https://github.com/llvm/llvm-project/pull/184547