Clarify that declarative string resolution does not imply imports are implicit
Clarify that declarative string resolution does not imply imports are implicit

Co-authored-by: Mike Bayer <mike_mp@zzzcomputing.com>
Closes: #4545
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/4545
Pull-request-sha: c25221838d726f316dc04102b6b2002cec6b3a6c

Change-Id: Ic38621f7deb3cb25e250aab61c5b2b02d633b187

j5int/sqlalchemy,graingert/sqlalchemy,sqlalchemy/sqlalchemy,graingert/sqlalchemy,wujuguang/sqlalchemy,monetate/sqlalchemy,wujuguang/sqlalchemy,monetate/sqlalchemy,j5int/sqlalchemy,zzzeek/sqlalchemy