Updated RgbwColor object API (markdown)

RgbwColor-object-API.md

@@ -123,4 +123,8 @@ This will blend between four colors by the amount defined by 2d weighting values
 The index operator allows accessing the R, G, B, and W properties using an index.  There are both read only and read write versions.
 ```
    uint8_t white = color[3];
+```
+You can also use the color index constants.  
+```
+   uint16_t white = color[ColorIndexW];
 ```