Rename ok to is_success on InternalHttpResponse

Taking some inspiration from httpx here, which I think had good reasoning for this change from requests.

wayback/_client.py

@@ -589,7 +589,7 @@ def redirect_url(self) -> str:
         return self._redirect_url
 
     @property
-    def ok(self) -> bool:
+    def is_success(self) -> bool:
         return self.status_code >= 200 and self.status_code < 300
 
     # XXX: This and _release_conn probably need wrapping with RLock!
@@ -1496,7 +1496,7 @@ def get_memento(self, url, timestamp=None, mode=Mode.original, *,
                         raise BlockedByRobotsError(f'{url} is blocked by robots.txt')
                     elif message:
                         raise MementoPlaybackError(f'Memento at {url} could not be played: {message}')
-                    elif response.ok:
+                    elif response.is_success:
                         # TODO: Raise more specific errors for the possible
                         # cases here. We *should* only arrive here when
                         # there's a redirect and:

wayback/tests/test_client.py

@@ -786,7 +786,7 @@ def test_request_retries(self, urllib3_mock):
                                              {'text': 'good', 'status_code': 200}])
         session = WaybackSession(retries=2, backoff=0.1)
         response = session.request('GET', 'http://test.com')
-        assert response.ok
+        assert response.is_success
 
         session.close()