message: Improve message doc comments
diff: @@ -14,9 +14,13 @@ pub enum Message {
  Lexer(LexerError),
  /// Errors produced during parsing
  Parse(ParseError),
  - /// Messages produced from [lang::core::typing]
  + /// Messages produced from [`lang::core::typing`]
  + ///
  + /// [`lang::core::typing`]: crate::lang::core::typing
  CoreTyping(CoreTypingMessage),
  - /// Messages produced from [pass::surface_to_core]
  + /// Messages produced from [`pass::surface_to_core`]
  + ///
  + /// [`pass::surface_to_core`]: crate::pass::surface_to_core
  SurfaceToCore(SurfaceToCoreMessage),
  }
  