updated Doxyfile

properly close all doxygen groups
fixed remaining doxygen warnings

src/libstrongswan/plugins/sha2/sha2_hasher.h

@@ -47,4 +47,4 @@ struct sha2_hasher_t {
  */
 sha2_hasher_t *sha2_hasher_create(hash_algorithm_t algorithm);
 
-#endif /* SHA2_HASHER_H_ @}*/
+#endif /** SHA2_HASHER_H_ @}*/

src/libstrongswan/plugins/sha2/sha2_plugin.h

@@ -44,4 +44,4 @@ struct sha2_plugin_t {
  */
 plugin_t *plugin_create();
 
-#endif /* SHA2_PLUGIN_H_ @}*/
+#endif /** SHA2_PLUGIN_H_ @}*/