Rollup merge of #78841 - LeSeulArtichaut:foldable-derive, r=lcnr
Rollup merge of #78841 - LeSeulArtichaut:foldable-derive, r=lcnr

Small cleanup in `TypeFoldable` derive macro

r? ```@lcnr```

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