Add missing retryable write case to pseudo code

[kkloberdanz]

The pseudo code example for executing retryable write commands was missing the case below:

• CSOT is not enabled and one retry was attempted.

This corrects the pseudo code to unify it with the prose description.

Related to: DRIVERS-1807

Please complete the following before merging:

• [ ] Update changelog.
• [ ] Make sure there are generated JSON files from the YAML test files.
• [ ] Test changes in at least one language driver.
• [ ] Test these changes against all server versions and topologies (including standalone, replica set, sharded clusters, and serverless).

[kkloberdanz]

The original pseudo code has some additional errata, which is documented in the ticket: https://jira.mongodb.org/browse/DRIVERS-2695

Closing for now.