fixes #25908; resolves lent enum disambiguation (#25929)

fixes #25908

When an enum identifier is resolved as an `nkSymChoice`, one of the
candidates may come from a loop-local view and carry `tyVar` or
`tyLent`.

Enum disambiguation should compare the underlying enum type only.
Otherwise a pure-enum field can win incorrectly even though the intended
symbol is already present in the choice set.

Keep the `includePureEnum` lookup path for enum-typed expectations so
#23976 still works, but normalize `var`/`lent` only at the symchoice
selection point.

tests/enum/tenum.nim

@@ -283,3 +283,13 @@ block: # bug #23952
       doAssert s1 != s2
     static: foo()
     foo()
+
+# bug #25908
+type S {.pure.} = enum a, b
+
+iterator foo(x: array[1, S]): lent S =
+  yield x[0]
+
+iterator f(_: int | int): S =
+  for a in foo([S.b]): yield a
+for v in f(0): doAssert v == S.b