refactor(http)!: fix cascade dart good practices + docs

packages/wyatt_http_client/lib/src/utils/authentication_methods.dart

@@ -14,8 +14,14 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
+/// Defines some authentication methods
 abstract class AuthenticationMethods {
+  /// The `Basic` authentication method.
   static const String basic = 'Basic';
+
+  /// The `Bearer` authentication method.
   static const String bearer = 'Bearer';
+
+  /// The `Digest` authentication method.
   static const String digest = 'Digest';
 }