Add new Performance/Squeeze cop

[fatkodima]

This cop will detect places where gsubing of multiple runs of single character by single character can be replaced by squeeze method.

# bad
str.gsub(/a+/, 'a')
str.gsub(/\\+/, '\\')
str.gsub!(/ +/, ' ')

# good
str.squeeze('a')
str.squeeze('\\')
str.squeeze!(' ')

Reference - https://github.com/JuanitoFatas/fast-ruby#remove-extra-spaces-or-other-contiguous-characters-code

[fatkodima]

Updated.

[koic]

Thanks!