DOC: Deprecation Warnings in user guide
#### Location of the documentation

https://pandas.pydata.org/docs/user_guide/indexing.html#indexing-deprecate-loc-reindex-listlike

#### Documentation problem

We have a lot of warnings in the documentation ``Starting with 0.x the following is deprecated.`` Most of these things stopped working with 1.0. Should we update the docs and say, that this stopped working with 1.0?
