On the tutorials page for annotations:

https://matplotlib.org/tutorials/text/annotations.html?highlight=connectionpatch

the entry for ConnectionPatch is mistitled ConnectorPatch, and ConnectorPatch is used in the text 3 times, and in the TOC (but not the example). Looks like the fix should be made here:

https://github.com/matplotlib/matplotlib/blob/master/tutorials/text/annotations.py

The same problem exists here:

https://matplotlib.org/users/annotations_guide.html#using-connectorpatch

But I can't find where this is in the current code base; from the page's header, it may be out-of-date.