write variables as #𝑖

previously non-coloured output was too ambiguous

lib/Quox/Syntax/Var.idr

@@ -62,7 +62,7 @@ parameters {auto _ : Pretty.HasEnv m}
   prettyVar' hlok hlerr names i =
     case inBounds i names of
          Yes _ => hlF' hlok [|prettyM (index i names) <+> prettyIndex i|]
-         No  _ => pure $ hl hlerr $ pretty i
+         No  _ => pure $ hl hlerr $ "#" <+> pretty i
 
   export %inline
   prettyVar : HL -> HL -> List Name -> Var n -> m (Doc HL)