Combine 'special' with 'specialFormat' as single resource format type

* There was no good reason to have a flag indicating if the special
  format was valid or not. Now it's a single enum, with a value
  'Regular' indicating that the compCount/compWidth/compType fully
  describe the format itself.
* This makes code patterns easier as you no longer need to check for
  special then check for specialFormat, you can just test the type
  directly.

qrenderdoc/Code/Interface/CommonPipelineState.cpp

@@ -808,7 +808,7 @@ QVector<VertexInputAttribute> CommonPipelineState::GetVertexInputs()
             ret[a].Format.compByteWidth = 4;
             ret[a].Format.compCount = compCount;
             ret[a].Format.compType = compType;
-            ret[a].Format.special = false;
+            ret[a].Format.type = ResourceFormatType::Regular;
             ret[a].Format.srgbCorrected = false;
           }
         }