When a block template or address is declared in multiple PSC layers, hover and
Go to Definition now resolve to the effective declaration (the one from the
last-loaded .def file). Find References and Rename still include all
declarations.
- add effective_def_locations(documents, target, uris) helper (returns the last declaration)
- use effective_def_locations in lsp_server for goto/definition endpoints
- change def_hover_markdown to show the effective declaration and append a short
"_Overrides ..._" note listing overridden declarations
- update changelog and add a test that verifies hover/GoTo reference the last
loaded declaration while references include all declarations