style(locations): lint-clean the unset-context filter

Replace the crash-prone set-membership filter with a truthiness dict
comprehension: never hashes the value (crash-robust for any parser input),
and satisfies the repo's ruff rules (no manual loop, no != "" comparison).
Drops None/""/0/empty — all "no data" for the code location's context
fields. Same fix, lint-clean form.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: Maffooch

dojo/tools/locations.py

@@ -68,9 +68,10 @@ def code(
             "source_file_path": source_file_path,
             "source_line": source_line,
         }
-        # Tuple (not set) membership: uses == rather than hashing, so an unset
-        # check never crashes on an unhashable value a parser might pass.
-        data.update({key: value for key, value in context.items() if value not in ("", None)})
+        # Truthiness filter (not set membership): never hashes `value`, so the
+        # unset check can't crash on an unhashable value a parser might pass.
+        # Drops None/""/0/empty — all "no data" for these context fields.
+        data.update({key: value for key, value in context.items() if value})
         return cls(type="code", data=data)
 
     @classmethod