Remove documents about `Regexp` argument from `String#{[],[]=}` [ci skip]
@@ -1228,8 +1228,6 @@ mrb_str_aref(mrb_state *mrb, mrb_value str, mrb_value indx, mrb_value alen)
* str[fixnum] => fixnum or nil
* str[fixnum, fixnum] => new_str or nil
* str[range] => new_str or nil
- * str[regexp] => new_str or nil
- * str[regexp, fixnum] => new_str or nil
* str[other_str] => new_str or nil
* str.slice(fixnum) => fixnum or nil
* str.slice(fixnum, fixnum) => new_str or nil
@@ -1437,8 +1435,6 @@ mrb_str_aset(mrb_state *mrb, mrb_value str, mrb_value indx, mrb_value alen, mrb_
* str[fixnum] = replace
* str[fixnum, fixnum] = replace
* str[range] = replace
- * str[regexp] = replace
- * str[regexp, fixnum] = replace
* str[other_str] = replace
*
* Modify +self+ by replacing the content of +self+.
