Emit `'_` for lifetime generics in `HirDisplay` This makes the generated code not linted by `rust_2018_idioms` lint. But that is an allow by default lint, so should we do this? Maybe we should only do this for `DisplayTarget::SourceCode`?
_
need-mut
'_
HirDisplay
DefMap
Name
${count()}
retain_mut
CommentBlock::extract