[expr.prim.id.unqual] name of coroutine parameter copy inside a lambda

[t3nsor]

Full name of submitter: Brian Bi

Issue description: After P2900R14, in cases where [expr.prim.id.unqual]/3+a applies, we do not fall through to 3+b, which says that the result of the unqualified-id is the parameter copy. Therefore, the result now refers to the original parameter.

Suggested resolution: We should keep all the description of what entity the unqualified-id refers to in p3.

Edit [expr.prim.id.unqual]/3:

The result is the entity denoted by the unqualified-id ([basic.lookup.unqual]), except that if that entity is a coroutine parameter, the result is instead the copy of that parameter ([dcl.fct.def.coroutine]).

Edit [expr.prim.id.unqual]/3+b:

Otherwise, if the unqualified-id names entity is the copy of a coroutine parameter, the type of the expression is that of the copy of the parameter ([dcl.fct.def.coroutine]), and the result is that copy. the type of the entity.