Minor corrections to v8 compatibility doc

[stevejgordon]

As titled

[stevejgordon]

Test failures are unrelated.

[github-actions]

The backport to 7.x failed:

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

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-7.x 7.x
# Navigate to the new working tree
cd .worktrees/backport-7.x
# Create a new branch
git switch --create backport-6265-to-7.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick --mainline 1 d613be37af9bbd37bdf5ce916493ed5f4e7761ea
# Push it to GitHub
git push --set-upstream origin backport-6265-to-7.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-7.x

Then, create a pull request where the base branch is 7.x and the compare/head branch is backport-6265-to-7.x.