Rollup merge of #52858 - frewsxcv:frewsxcv-elaborator, r=SimonSapin
Rollup merge of #52858 - frewsxcv:frewsxcv-elaborator, r=SimonSapin

Implement Iterator::size_hint for Elaborator.

None

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