Rollup merge of #34467 - GuillaumeGomez:err-codes, r=brson
Rollup merge of #34467 - GuillaumeGomez:err-codes, r=brson

Add new error codes and improve some explanations

r? @brson

cc @steveklabnik
cc @jonathandturner

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