Rollup merge of #145381 - Gnurou:int_lowest_highest_one, r=jhpratt

Implement feature `int_lowest_highest_one` for integer and NonZero types

Tracking issue: rust-lang/rust#145203

Implement the accepted ACP rust-lang/rust#145203 for methods that find the index of the least significant (lowest) and most significant (highest) set bit in an integer for signed, unsigned, and NonZero types.

Also add unit tests for all these types.

Author: jhpratt