For a 1.4 / 1.3 merge, rewrite the documentation for
Query.join() to indicate calling forms that are now considered
legacy, including the use of strings in join(), sending a
series of join paths in one call, and using the aliased=True
flag.   update the elementtree examples as well to use aliased()
(they are much simpler to understand this way too) and update
other links.

Also improve docs for aliased() and some other ORM targets
such as PropComparator.

Change-Id: I636e3a9130dc5509e51c2cf60a52f38fcadffbc6
References: #4705

<!-- Provide a general summary of your proposed changes in the Title field above -->

### Description
<!-- Describe your changes in detail -->
Remove print statements

### Checklist
<!-- go over following points. check them with an `x` if they do apply, (they turn into clickable checkboxes once the PR is submitted, so no need to do everything at once)

-->

This pull request is:

- [X] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [ ] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #5166
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5166
Pull-request-sha: 04a7394f71298322188f0861b4dfe93e5485839d

Change-Id: Ib90a59fac929661a18748c6e44966fb87e3978c6

This is a very useful assertion which prevents unused variables
from being set up allows code to be more readable and sometimes
even more efficient.  test suites seem to be where the most
problems are and there do not seem to be documentation examples
that are using this, or at least the linter is not taking effect
within rst blocks.

Change-Id: I2b3341d8dd14da34879d8425838e66a4b9f8e27d

Partially fixes sqlalchemy/sqlalchemy#4426.

Closes: #4441
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/4441
Pull-request-sha: ed90f3b77c2d0f4cc2cd54f40f5af29b489977d2

Change-Id: Ic32e5d8020073da055b12a6aeb61e698a97dc504

Applied on top of a pure run of black -l 79 in
I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9,  this set of changes
resolves all remaining flake8 conditions for those codes
we have enabled in setup.cfg.

Included are resolutions for all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.

Change-Id: I4f72d3ba1380dd601610ff80b8fb06a2aff8b0fe

This is a straight reformat run using black as is, with no edits
applied at all.

The black run will format code consistently, however in
some cases that are prevalent in SQLAlchemy code it produces
too-long lines.   The too-long lines will be resolved in the
following commit that will resolve all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.

Change-Id: I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9

to allow ad-hoc display of the source of any file, as well as a "directory listing" structure.
- reorganize examples/ to take advantage of new extension.  in particular, keep moving all
the descriptive text for files etc. into module docstrings, taking more advantage of
self-documentation.

- went through examples/ and cleaned out excess list() calls