doc: provide an actual equivalent to filter_map
doc: provide an actual equivalent to filter_map

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