Auto merge of #6585 - Daniel-B-Smith:false-positive-issue, r=flip1995
Auto merge of #6585 - Daniel-B-Smith:false-positive-issue, r=flip1995

Explicitly document false positives

Adds documentation for known false positives for the `await_holding*` lints.

Issues:

https://github.com/rust-lang/rust-clippy/issues/6353
https://github.com/rust-lang/rust-clippy/issues/6446

changelog: document FPs for the ``await_holding_*`` lints

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust