Auto merge of #29074 - Manishearth:astconv-doc, r=eddyb
Auto merge of #29074 - Manishearth:astconv-doc, r=eddyb

Confusion about what this does caused a bug in Servo's lints.

r? @eddyb

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