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

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.

would produce an empty WHERE clause when an empty :func:`.and_()`
or :func:`.or_()` or other blank expression were applied.  This is
now consistent with that of :func:`.select`.
fixes #3045

"SELECT FIRST n ROWS" using a bound parameter (only firebird has both),
combined with column-level subqueries
which also feature "limit" as well as "positional" bound parameters
(e.g. qmark style) would erroneously assign the subquery-level positions
before that of the enclosing SELECT, thus returning parameters which
are out of order. Fixes #3038

Found using: https://github.com/intgr/topy

a join condition that is strictly from a single column to itself,
translated through some kind of SQL function or expression.  This
is kind of experimental, but the first proof of concept is a
"materialized path" join condition where a path string is compared
to itself using "like".   The :meth:`.Operators.like` operator has
also been added to the list of valid operators to use in a primaryjoin
condition.  fixes #3029