Enable the diagnostics which already pass

These were carried over as disabled from the luals config but report
nothing, so they only ever masked a future regression.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.emmyrc.json

@@ -22,18 +22,13 @@
         "globals": [ "__DebugAdapter", "__Profiler" ],
         "disable": [
             "assign-type-mismatch",
-            "await-in-sync",
-            "invert-if",
             "missing-parameter",
-            "missing-return-value",
             "param-type-mismatch",
             "preferred-local-alias",
             "redefined-local",
             "redundant-parameter",
             "redundant-return-value",
             "return-type-mismatch",
-            "unbalanced-assignments",
-            "undefined-doc-param",
             "unnecessary-assert",
             "unnecessary-if",
             "unused"