This patch adds new warnings for all elements that
don't indicate their caching behavior, including user-defined
ClauseElement subclasses and third party dialects.
it additionally adds new documentation to discuss an apparent
performance degradation in 1.4 when caching is disabled as a
result in the significant expense incurred by ORM
lazy loaders, which in 1.3 used BakedQuery so were actually
cached.

As a result of adding the warnings, a fair degree of
lesser used SQL expression objects identified that they did not
define caching behavior so would have been producing
``[no key]``, including PostgreSQL constructs ``hstore``
and ``array``.  These have been amended to use inherit
cache where appropriate.  "on conflict" constructs in
PostgreSQL, MySQL, SQLite still explicitly don't generate
a cache key at this time.

The change also adds a test for all constructs via
assert_compile() to assert they will not generate cache
warnings.

Fixes: #7394
Change-Id: I85958affbb99bfad0f5efa21bc8f2a95e7e46981

Change-Id: I8172fdcc3103ff92aa049827728484c8779af6b7

References: #4600
Change-Id: I2a62ddfe00bc562720f0eae700a497495d7a987a

Fixes: #6960

Even though a default driver still exists for
each dialect, remove most usages of `dialect://`
to encourage users to explicitly specify
`dialect+driver://`

Change-Id: I0ad42167582df509138fca64996bbb53e379b1af

References: #4600
Change-Id: I61e35bc93fe95610ae75b31c18a3282558cd4ffe

- Fixed import to avoid MovedIn20Warning.

- Separated drop_all() and create_all() into separate
context managers to avoid dropping and creating the
same table within the same transaction. Apparently
some databases (e.g., CockroachDB) don't allow that.

Change-Id: Id26d7d719871a75ffb78c6af589658666802fb2f

Repaired the examples in examples/versioned_rows to use SQLAlchemy 1.4 APIs
correctly; these examples had been missed when API changes like removing
"passive" from ``Session.is_modified()`` were made as well as the
``do_orm_execute()`` event hook were added.

Fixes: #7169
Change-Id: I30930a3b185dc0f73be4467faa2f97c5ebf1a36d

Updated elementtree example to replace the deprecated classical mappings
interface with the current `registry.map_imperatively()` version.

The examples STILL use classical mappings, so the ticket remains open.
This update merely removes the deprecated API in favor of the (temporary?) replacement.

Change-Id: I8ddb86b76d82ac9d87a55edb0225e6b2f6ab4940

* fix: lib/sqlalchemy/sql/lambdas.py

* fix: lib/sqlalchemy/sql/compiler.py

* fix: lib/sqlalchemy/sql/selectable.py

* fix: lib/sqlalchemy/orm/relationships.py

* fix: lib/sqlalchemy/dialects/mssql/base.py

* fix: lib/sql/test_compiler.py

* fix: lib/sqlalchemy/testing/requirements.py

* fix: lib/sqlalchemy/orm/path_registry.py

* fix: lib/sqlalchemy/dialects/postgresql/psycopg2.py

* fix: lib/sqlalchemy/cextension/immutabledict.c

* fix: lib/sqlalchemy/cextension/resultproxy.c

* fix: ./lib/sqlalchemy/dialects/oracle/cx_oracle.py

* fix: examples/versioned_rows/versioned_rows_w_versionid.py

* fix: examples/elementtree/optimized_al.py

* fix: test/orm/test_attribute.py

* fix: test/sql/test_compare.py

* fix: test/sql/test_type_expression.py

* fix: capitalization in test/dialect/mysql/test_compiler.py

* fix: typos in test/dialect/postgresql/test_reflection.py

* fix: typo in tox.ini comment

* fix: typo in /lib/sqlalchemy/orm/decl_api.py

* fix: typo in test/orm/test_update_delete.py

* fix: self-induced typo

* fix: typo in test/orm/test_query.py

* fix: typos in test/dialect/mssql/test_types.py

* fix: typo in test/sql/test_types.py

while I dont like this approach very much, people will likely
be asking for it a lot, so represent the most correct and
efficient form we can handle right now.

Added missing ``**kw`` arguments to the
:meth:`_asyncio.AsyncSession.connection` method.

Change-Id: Idadae2a02a4d96ecb96a5723ce64d017ab4c6217
References: https://github.com/sqlalchemy/sqlalchemy/discussions/6965