Implement support for `WAIT` (generic command)

[cunla]

Implement support for command WAIT in generic_mixin.py.

Blocks until the asynchronous replication of all preceding write commands sent by the connection is completed..

Here is the Official documentation

Upvote & Fund

• We're using Polar.sh so you can upvote and help fund this issue.
• We receive the funding once the issue is completed & confirmed by you.
• Thank you in advance for helping prioritize & fund our backlog.