Auto merge of #4465 - JohnTitor:add-note-to-fix-toolstate, r=flip1995
Auto merge of #4465 - JohnTitor:add-note-to-fix-toolstate, r=flip1995

Add note to fix toolstate

The idea from https://github.com/rust-lang/rust-clippy/pull/4462#issuecomment-525725587
It's nice that we have the documentation to guide fix toolstate.

changelog: none

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