snippet: Updated all snippet tags

Ensure all src C++ headers which have corresponding C++ examples have
doxygen tags which point to those examples.  Some were missing, some
were invalid, some needed to be updated to match the new example names.

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/waterlevel/waterlevel.hpp

@@ -45,7 +45,7 @@ namespace upm {
    * it may actuate a pump, an indicator, an alarm, or other devices.
    *
    * @image html waterlevel.jpg 
-   * @snippet apds9002.cxx Interesting
+   * @snippet waterlevel.cxx Interesting
    */
   class WaterLevel {
   public: