Doc: fix issue with Unicode zero-width space character and PDF output

[rouault]

Fixes #11162

[rouault]

cherry-picked to 3.10 per 7a55cf2 and efd3ed1

[rouault]

The backport to release/3.10 failed:

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

stderr

The previous cherry-pick is now empty, possibly due to conflict resolution.
If you wish to commit it anyway, use:

    git commit --allow-empty

Otherwise, please use 'git cherry-pick --skip'

stdout

On branch backport-11166-to-release/3.10
You are currently cherry-picking commit 289b9ea5df.
  (all conflicts fixed: run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

nothing to commit, working tree clean

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-release/3.10 release/3.10
# Navigate to the new working tree
cd .worktrees/backport-release/3.10
# Create a new branch
git switch --create backport-11166-to-release/3.10
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 289b9ea5dff283b911143a8b079c8dd39e2a78eb,38aaedb2fe372ccdbeeecf92581af5bb9a278ee1
# Push it to GitHub
git push --set-upstream origin backport-11166-to-release/3.10
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.10

Then, create a pull request where the base branch is release/3.10 and the compare/head branch is backport-11166-to-release/3.10.