The locale is ignored when indexing documents

On page move, backlinks in translated documents are not refactored if not present in the original document. The root cause is that translated documents are not indexed. Caused by XWIKI-19378.

While the problem already existed before XWIKI-19378, the mention notification does not work on translated documents, see XWIKI-19621.

Steps to reproduce

In a multilingual EN/FR main wiki with EN as default language:

• Create page Sandbox.A.WebHome in EN with a link to Sandbox.B.WebHome in its content
• Translate Sandbox.A.WebHome to FR with links to Sandbox.B.WebHome and to Sandbox.C.WebHome in its content
• Create pages Sandbox.B.WebHome and Sandbox.C.WebHome in EN (at this point, you can check the backlinks of Sandbox.C.WebHome, it is empty instead of containing Sandbox.A.WebHome.
• Move Sandbox.B.WebHome to Sandbox.B1.WebHome
• Move Sandbox.C.WebHome to Sandbox.C1.WebHome

Actual result

In Sandbox.A.WebHome, the links to doc:Sandbox.B.WebHome in EN and FR versions are refactored as expected to doc:Sandbox.B1.WebHome, however the link to Sandbox.C.WebHome in the FR version is not refactored to Sandbox.C1.WebHome, which is unexpected. Before the move, the information tab of Sandbox.C.WebHome does not show Sandbox.A.WebHome as a backlink so the issue seems to be due to an incorrect computation or storage of backlinks located in translated documents.

I noticed the bug in version 14.2.1 but could not reproduce it in version 13.10.3.