Auto merge of #43619 - frewsxcv:frewsxcv-thread, r=QuietMisdreavus
Auto merge of #43619 - frewsxcv:frewsxcv-thread, r=QuietMisdreavus

Thread docs fix and improvements.

None

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