6721ddcf

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

Ask for a tag or a ref where a comment couples two named places

CommentCouplingConnection reports a comment that says two places move together
and names one of them as code, when no comment in the same scope carries a
tagref or marginalia pair.

Two signals rather than one, because neither half stands up alone. Tried out
over nix-ci8, a thousand modules: the phrase alone reported nine comments and
six were wrong, four of them saying the program keeps a database row in sync
with an external forge at run time and two arguing there is deliberately no
second place to keep. A marked name alone reported twenty-two and none worth
acting on, because naming a sibling definition to orient a reader is what good
Haddock is made of. Together they report one, which is the coupling.

The cost is recall: prose that names no place, as tagref's own example does,
is now silent. good.hs pins that as a decision rather than an accident.