Fix Ruby 3.4 frozen string warnings in normalize_input

[mavegaf]

Ruby 3.4 enables frozen string literals by default, which causes warnings when using destructive string methods (like strip! and downcase!) on frozen strings. This commit replaces the usage of input.clone.tap { |str| str.strip!; str.downcase! } with a non-mutating chain input.to_s.strip.downcase, which avoids mutating the original string and eliminates the warnings.

References:

• Ruby issue: https://bugs.ruby-lang.org/issues/20205

[jonh-favo]

Any plans to review/merge this pull request?

[cavi21]

@jfairbank (Thanks for the work on this gem 🙌) would you consider merging this PR?

Since the use of clone persist the frozen state of the string literal, not sure what was the intention with it? and since this method is called for asigning the returned value to a variable the proposed solution is safer and don't require a dup neither, right? or I'm missing something?