ALS should highlight known aspects to provide feedback to the user

[manthonyaiello]

Ada has many aspects that are introduced using the keyword with. For example, especially with SPARK, we may place many aspects on suprograms:

   procedure Parse_Formula
     (Formula : Unbounded_String;
      Algebra : out Algebra_Tree;
      Error   : in out Boolean;
      Message : in out Unbounded_String)
   with
     Pre  => Length (Formula) > 1,
     Post => (if not Error then Algebra /= null),
     Subprogram_Variant => (Decreases => Length (Formula));

Currently, these are not highlighted at all. It would be helpful to the user if known aspects received some subtle syntax highlight, so that they know they've used a known aspect.