interfaces with implementors that override `__init__` seem to create implicit ambiguous references to their interface's `__init__` method

[glyph]

Various errors in Twisted's trunk right now say things like

src/twisted/web/iweb.py:687: Cannot find link target for "__init__"

the line numbers appear to be nonsense, but correspond to implementors with custom __init__s. Stubbing out a fake __init__ seems to work around it.

[tristanlatr]

Hi @glyph and thank you for the issue report. This does look like a bug. A minimal reproducer would be good :) Tell me if you have time to work on this in the coming weeks ? Thanks