Rollup merge of #80464 - LingMan:map_or, r=oli-obk
Rollup merge of #80464 - LingMan:map_or, r=oli-obk

Use Option::map_or instead of open coding it

``@rustbot`` modify labels +C-cleanup +T-compiler

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