As documented in VEP-4, we have started the process of migrating to standard pflag usage.
Some of the docs don't yet reflect the recommended usage, so we need to fix those
https://vitess.io/docs/14.0/reference/programs/vtexplain/
https://vitess.io/docs/14.0/reference/programs/vtgate/

The rest (mysqlctl, vtctl, vtctld, vtadmin, vttablet) are correct. However, there is inconsistency in how the flags are listed. In some cases they are prefixed with --, in others, there is no prefix. We should make them all standard, my suggestion is to drop the -- prefix.