Menu Item autocomplete field only autocompletes node paths

Problem/Motivation

Drupal nowadays includes a cool feature that allows you to autocomplete paths when adding menu links. Unfortunately the MenuLink Autocomplete field can only autocomplete paths for nodes, ignoring other content entities (e.g. taxonomy terms).

Steps to reproduce

1. Create a node of whatever content type (e.g. basic page);
2. Create a taxonomy term
3. Go to https://yourdrupalsite/admin/structure/menu/manage/main/add
4. Start typing in the "path" autocomplete field the title of the node you created in step 1: notice how the field nicely autocompletes the reference for you.
5. Do the same for the taxonomy term you created in step 2: nothing happens, you have to enter the full path in the old (un)fashioned way.

Proposed resolution

Menu link autocomplete field should autocomplete paths for each content entity, not only nodes; if unfeasible, it should at least include taxonomy terms.

Remaining tasks

Discuss and fix.

User interface changes

None

API changes

TBD

Data model changes

TBD, hopefully none.

Release notes snippet

TBD