Convert the three extension/substitution-pass compile checkers to located
findings so each error attaches to its declaring node instead of the schema
root (#169): an xs:all group reached through an extension over a base that
already has content underlines the extension (extensionAllGroupFindings); an
anonymous complex-type restriction that is not a subset of its base
underlines the restriction (anonymousRestrictionFindings); and a
substitution-group member whose type is not validly derived from its head,
including the head's final-exclusion violations, underlines the member
element (substitutionTypeFindings).
Every predicate, iteration order, and reason string is unchanged; only the
location each finding carries differs, verified conformance-neutral by the
full XSTS suite (14383 groups, pinned counts unchanged). The
substitution checker's checkExclusions helper stays [String] and is wrapped
onto the member element at the call site. 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 checker.
Mihaela Mihaljevic
c6dd0f7d2f