message: Avoid superfluous spaces in doc-comment codegen
diff: @@ -76,8 +76,9 @@ fn lower_doc_comment<'doc, 'a: 'doc, A: DocAllocator<'doc>>(
  if comment.is_empty() {
  doc.nil()
  } else {
  - doc.concat(comment.lines().map(|line| {
  - doc.text(format!("/// {}", line)).append(doc.newline())
  + doc.concat(comment.lines().map(|line| match line {
  + "" => doc.text("///").append(doc.newline()),
  + _ => doc.text(format!("/// {}", line)).append(doc.newline()),
  }))
  }
  }
  