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/ds1808lc/ds1808lc.hpp

@@ -48,6 +48,7 @@ namespace upm
  * @type light
  * @man maxim
  * @con i2c
+ * @snippet ds1808lc.cxx Interesting
  * @if ilightcontroller
  */
 class DS1808LC : public upm::ILightController