Rollup merge of #60376 - lzutao:stabilize-option_xor, r=SimonSapin
Rollup merge of #60376 - lzutao:stabilize-option_xor, r=SimonSapin

Stabilize Option::xor

FCP done in https://github.com/rust-lang/rust/issues/50512#issuecomment-469527554 .

Closes #50512 .

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