Typo in description of casecmp?

Description of `casecmp?` mentions `other_other_str` instead of `other_str`

```
casecmp?(other_str) → true, false, or nil
Returns true if str and other_other_str are equal after Unicode case folding, false if they are not equal, and nil if other_str is not a string.
```

https://ruby-doc.org/core-2.4.3/String.html