Search broken on docs

```
1. Browse to https://gmpy2.readthedocs.org/en/latest/
2. In the search box, search for 'isqrt'
3. No results.

Should find https://gmpy2.readthedocs.org/en/latest/mpz.html


```

Original issue reported on code.google.com by `matt.hickford` on 28 Apr 2013 at 4:25
