Merge 4.2 into 4.3

[mongodb-php-bot]

Merge new changes from 4.2 into 4.3.

Commits

• Merge 4.1 into 4.2 (Merge 4.1 into 4.2 #2854): 0e2ab47
• DOCSP-35968: Transactions docs (DOCSP-35968: Transactions docs #2847): 79df465

Resolving conflicts

To resolve any conflicts, check out the temporary branch and run the following command:

git merge 4.3

Ignoring changes

To ignore from the remote branch, first reset the temporary branch to 4.3 and manually merge using the `ours` merge strategy:

git reset --hard 4.3
git merge --strategy=ours 4.2

Then, push the temporary branch to upate the pull request.

[ccho-mongodb]

LGTM!