sync warning settings

_CoqProject

 -Q theories actris
--arg -w -arg -notation-overridden,-redundant-canonical-projection,-several-object-files,-convert_concl_no_check,-undeclared-scope,-ambiguous-paths,-unexpected-implicit-declaration
+# We sometimes want to locally override notation, and there is no good way to do that with scopes.
+-arg -w -arg -notation-overridden
+# Cannot use non-canonical projections as it causes massive unification failures
+# (https://github.com/coq/coq/issues/6294).
+-arg -w -arg -redundant-canonical-projection
+
 theories/utils/skip.v
 theories/utils/llist.v
 theories/utils/compare.v