Update colors.xml with comment for color used by activity embedding snippets.

Author: JonEckenrode

misc/src/main/res/values/colors.xml

@@ -7,5 +7,6 @@
     <color name="teal_700">#FF018786</color>
     <color name="black">#FF000000</color>
     <color name="white">#FFFFFFFF</color>
+    <!-- For activity embedding snippets. -->
     <color name="divider_color">#FFFFAA00</color>
 </resources>