Convert the three names/UPA/notation-pass compile checkers to located
findings so each error attaches to its declaring node instead of the schema
root (#169): component-name uniqueness underlines the second duplicate global,
identity-constraint name uniqueness underlines the second constraint, a
keyref whose refer names no key/unique (or whose arity differs) underlines
the keyref (KeyrefInfo gains the keyref node), a Unique Particle Attribution
violation underlines the ambiguous content-model group, and notation
validity underlines the notation or enumeration.
Every predicate, aggregation order, reason string, and the message-dedup of
the UPA pass are unchanged; only the location each finding carries differs,
verified conformance-neutral by the full XSTS suite (14383 groups, pinned
counts unchanged). The findUniqueIndices circular-import (rootIndex)
workaround is left byte-identical, since it governs which containers are
examined, not where findings locate. The three checkers had exactly one
caller each (their dispatch), so each is renamed in place and the .unlocated
wrap dropped. Adds a located-diagnostics test per sub-check.
Mihaela Mihaljevic
96ab396eb3