Update documentation: complete client docs for honoring proxy env vars

[celloni]

What do these changes do?

• Update proxy support docs to honor no_proxy env
• Complete trust_env parameter description to honor wss_proxy, ws_proxy or no_proxy env

Are there changes in behavior for the user?

No

Related issue number

Update docs for: #4431

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt
  • The format is <Name> <Surname>.
  • Please keep alphabetical order, the file is sorted by names.
• Add a new news fragment into the CHANGES folder
  • name it <issue_id>.<type> for example (588.bugfix)
  • if you don't have an issue_id change it to the pr id after creating the pr
  • ensure type is one of the following:
    • .feature: Signifying a new feature.
    • .bugfix: Signifying a bug fix.
    • .doc: Signifying a documentation improvement.
    • .removal: Signifying a deprecation or removal of public API.
    • .misc: A ticket has been closed, but it is not of interest to users.
  • Make sure to use full sentences with correct case and punctuation, for example: "Fix issue with non-ascii contents in doctest text files."

[Dreamsorcerer]

I'm not sure that's accurate, but I'd rather we linked to the documentation upstream here.
We just call https://docs.python.org/3/library/urllib.request.html#urllib.request.getproxies
Then the code filters the results to get proxies for these schemes: ("http", "https", "ws", "wss")

[celloni]

Thanks a lot for the reply. Indeed this is more accurate. I tried to address the comment by linking to upstream in client_advanced#proxy-support and simplifying the rest by referencing to client_advanced#proxy-support

[codecov]

Codecov Report

Merging #7235 (f98859c) into master (3ff81dc) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #7235      +/-   ##
==========================================
- Coverage   97.31%   97.31%   -0.01%     
==========================================
  Files         107      107              
  Lines       31352    31405      +53     
  Branches     3901     3926      +25     
==========================================
+ Hits        30511    30562      +51     
  Misses        640      640              
- Partials      201      203       +2     

Flag	Coverage Δ
CI-GHA	97.22% <ø> (-0.01%)	⬇️
OS-Linux	96.87% <ø> (-0.01%)	⬇️
OS-Windows	95.30% <ø> (-0.01%)	⬇️
OS-macOS	96.46% <ø> (-0.01%)	⬇️
Py-3.10.10	?
Py-3.10.11	96.98% <ø> (?)
Py-3.11.0	96.40% <ø> (-0.01%)	⬇️
Py-3.7.15	?
Py-3.7.16	96.69% <ø> (+0.12%)	⬆️
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Py-3.9.16	96.62% <ø> (-0.01%)	⬇️
Py-pypy7.3.11	94.11% <ø> (-0.04%)	⬇️
VM-macos	96.46% <ø> (-0.01%)	⬇️
VM-ubuntu	96.87% <ø> (-0.01%)	⬇️
VM-windows	95.30% <ø> (-0.01%)	⬇️

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[patchback]

Backport to 3.9: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 1c49738 on top of patchback/backports/3.9/1c4973881f9f49e65720b89b194cc1d327e5bd32/pr-7235

Backporting merged PR #7235 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.9/1c4973881f9f49e65720b89b194cc1d327e5bd32/pr-7235 upstream/3.9

4. Now, cherry-pick PR Update documentation: complete client docs for honoring proxy env vars #7235 contents into that branch:

   $ git cherry-pick -x 1c4973881f9f49e65720b89b194cc1d327e5bd32

   If it'll yell at you with something like fatal: Commit 1c4973881f9f49e65720b89b194cc1d327e5bd32 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 1c4973881f9f49e65720b89b194cc1d327e5bd32

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Update documentation: complete client docs for honoring proxy env vars #7235 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.9/1c4973881f9f49e65720b89b194cc1d327e5bd32/pr-7235

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[Dreamsorcerer]

If you could handle the backport, as above, that would be great.

[celloni]

Created the backport here #7256