Document web.FileResponse

[Transfusion]

What do these changes do?

Adds FileResponse constructor parameters to the documentation, based on the parent StreamResponse class documentation.

Related issue number

Resolves #3958

Checklist

• Documentation reflects the changes
• 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."

[webknjaz]

Thanks @Transfusion!

[patchback]

Backport to 3.10: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 7a59a14 on top of patchback/backports/3.10/7a59a1480b7cca4779c62fe35be778415121cd71/pr-3991

Backporting merged PR #3991 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/3.10/7a59a1480b7cca4779c62fe35be778415121cd71/pr-3991 upstream/3.10

4. Now, cherry-pick PR Document web.FileResponse #3991 contents into that branch:

   $ git cherry-pick -x 7a59a1480b7cca4779c62fe35be778415121cd71

   If it'll yell at you with something like fatal: Commit 7a59a1480b7cca4779c62fe35be778415121cd71 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 7a59a1480b7cca4779c62fe35be778415121cd71

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Document web.FileResponse #3991 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/7a59a1480b7cca4779c62fe35be778415121cd71/pr-3991

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
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my source is open — https://github.com/sanitizers/patchback-github-app.