[TASK] Rename and move the page about AjaxRequest

[brotkrueml]

Previously, the page was called "Ajax, client-side" but was about TYPO3's AjaxRequest API. The page is renamed to "Ajax request" to make more clear what is the content of the page. Additionally, it is moved into the Backend/JavaScript folder wher other JavaScript APIs reside.

Related: #2331
Releases: main, 12.4

[linawolf]

Will you make the redirects right after merging?

[brotkrueml]

Will you make the redirects right after merging?

@linawolf Where can I do that?

[linawolf]

@brotkrueml you should have the nessecary rights at intercept? https://intercept.typo3.com/redirect/

[github-actions]

The backport to 12.4 failed:

The process '/usr/bin/git' failed with exit code 1

stderr

error: could not apply 5e57240e... [TASK] Rename and move the page about AjaxRequest
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".

stdout

Auto-merging Documentation/ApiOverview/Backend/JavaScript/Index.rst
CONFLICT (content): Merge conflict in Documentation/ApiOverview/Backend/JavaScript/Index.rst

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-12.4 12.4
# Navigate to the new working tree
cd .worktrees/backport-12.4
# Create a new branch
git switch --create backport-3475-to-12.4
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 5e57240eb26f7d19a6f9ebe742c92af8775e55c8
# Push it to GitHub
git push --set-upstream origin backport-3475-to-12.4
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-12.4

Then, create a pull request where the base branch is 12.4 and the compare/head branch is backport-3475-to-12.4.