DOC:  Documentation for MultiIndex.get_locs() is missing in v0.25 docs
#### Problem description

The documentation for `MultiIndex.get_locs()` is missing in v0.25 docs (at least since v0.23?)

It is referred to here: 
https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.MultiIndex.get_loc.html

And it existed in v0.22:
https://pandas.pydata.org/pandas-docs/version/0.22/generated/pandas.MultiIndex.get_locs.html

Mentioned in #29967 