when that :class:`.Column` is referred to in an explicit
:class:`.PrimaryKeyConstraint` for that table.  This behavior now
matches that of when the :class:`.Column` itself has the
:paramref:`.Column.primary_key` flag set to ``True``, which is
intended to be an exactly equivalent case.
fixes #3023

Moved initialization into else block
Conflicts:
	lib/sqlalchemy/sql/compiler.py

UNION would wrap the union in an anonymous (e.g. unlabled) subquery.
fixes #3044

due to repeats would not correctly be rewritten in subqueries.
This would affect SELECT queries with any kind of subquery + join.
fixes #3057

:meth:`.Operators.__or__` and :meth:`.Operators.__invert__`
operator overload methods could not be overridden within a custom
:class:`.TypeEngine.Comparator` implementation.
fixes #3012

- add language to MATCH explicitly stating this operator varies by backend and is not available
on SQLite, as the tutorial defaults to SQLite to start with, fix #3059
- on the actual match() documentation fix this up to be more accurate, list some example renderings
for different backends.  again mention SQLite not supported

- add new FAQ for rendering SQL as a string

- implement for SQL server, use window functions when simple limit/offset not available

Removed ungrammatical apostrophes from documentation, replacing
"it's" with "its" where appropriate (but in a few cases with "it is"
when that read better).

While doing that, I also fixed a couple of minor typos etc.
as I noticed them.