Remove ALL keyword from TABLES IN SCHEMA for publication

Remove ALL keyword from TABLES IN SCHEMA for publication

This may be a bit too subtle, but removing that word from there makes
this clause no longer a perfect parallel of the GRANT variant "ALL
TABLES IN SCHEMA": indeed, for publications what we record is the schema
itself, not the tables therein, which means that any tables added to the
schema in the future are also published.  This is completely different
to what GRANT does, which is affect only the tables that exist when the
command is executed.

There isn't resounding support for this change, but there are a few
positive votes and no opposition.  Because the time to 15 RC1 is very
short, let's get this out now.

Backpatch to 15.

Discussion: https://postgr.es/m/2729c9e2-9aac-8cda-f2f4-34f2bcc18f4e