Link Integrity: addition requested

[danielamormocea]

Regarding https://github.com/plone/volto/pull/3317 it would be nice if the api could give us more info regarding link integrity breaches. For the moment linkintegrity api does not detect objects referenced by a text block link, neither does it tell enough information regarding breaches (e.g. if we have a page A, and then a page B and inside page B there is a page C; if I reference page C in page A and then try to delete page B, it tells me that the breach is between page B and page A, and I think it would be useful to mention page C there as well).