Function is_param_name_suffix_of_fn_name 

fn is_param_name_suffix_of_fn_name(param_name: &str, fn_name: &str) -> bool

Hide the parameter name of a unary function if it is a _ - prefixed suffix of the function’s name, or equal.

fn strip_suffix(suffix) will be hidden. fn stripsuffix(suffix) will not be hidden.