[TASK] Use "TYPO3 Explained" instead of "Core API document"

[brotkrueml]

Releases: main, 12.4, 11.5

[github-actions]

The backport to 11.5 failed:

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

stderr

error: could not apply 81bd019... [TASK] Use "TYPO3 Explained" instead of "Core API document"
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/Introduction/Index.rst
CONFLICT (content): Merge conflict in Documentation/Introduction/Index.rst
Auto-merging Documentation/PageTsconfig/TceMain.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-11.5 11.5
# Navigate to the new working tree
cd .worktrees/backport-11.5
# Create a new branch
git switch --create backport-372-to-11.5
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 81bd0190aecbf5ec356b08c0f3b6f8a7fdf054a9
# Push it to GitHub
git push --set-upstream origin backport-372-to-11.5
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-11.5

Then, create a pull request where the base branch is 11.5 and the compare/head branch is backport-372-to-11.5.