Warning 4094 has a very confusing message

When warning 4094 occurs, I see messages like this:

Note (Code 4094): At line 8 in test.test0

This makes the warning confusing and not helpful. To add confusion, this warning is not listed in the relevant documentation pages:

• https://mariadb.com/kb/en/library/mariadb-error-codes/
• https://dev.mysql.com/doc/refman/8.0/en/error-messages-server.html

I'm not adding a test case because you already have several test cases where 4094 is supposed to occur.