lint: Prevent self: Any annotations.

We should omit these for mypy.  For most class definitions,
mypy doesn't need `Any`, and it provides no real useful info.

For clever monkeypatches, you should provide a more specific
type than `Any`.

tools/linter_lib/custom_check.py

@@ -264,6 +264,10 @@ def build_custom_checkers(by_lang):
          'description': 'Missing space around "%"',
          'good_lines': ["'%s' % ('foo')", "'%s' % (foo)"],
          'bad_lines': ["'%s'%('foo')", "'%s'%(foo)"]},
+        {'pattern': 'self: Any',
+         'description': 'you can omit Any annotation for self',
+         'good_lines': ['def foo (self):'],
+         'bad_lines': ['def foo(self: Any):']},
         # This rule is constructed with + to avoid triggering on itself
         {'pattern': " =" + '[^ =>~"]',
          'description': 'Missing whitespace after "="',

zerver/tests/test_attachments.py

@@ -23,7 +23,7 @@ class AttachmentsTests(ZulipTestCase):
         attachments = user_attachments(user_profile)
         self.assertEqual(result.json()['attachments'], attachments)
 
-    def test_remove_attachment_exception(self: Any) -> None:
+    def test_remove_attachment_exception(self) -> None:
         user_profile = self.example_user('cordelia')
         self.login(user_profile.email)
         with mock.patch('zerver.lib.attachments.delete_message_image', side_effect=Exception()):

zerver/tests/test_signup.py

@@ -2269,7 +2269,7 @@ class UserSignUpTest(ZulipTestCase):
         self.assertEqual(result.status_code, 302)
         self.assertEqual(get_session_dict_user(self.client.session), user_profile.id)
 
-    def test_registration_of_active_mirror_dummy_user(self: Any) -> None:
+    def test_registration_of_active_mirror_dummy_user(self) -> None:
         """
         Trying to activate an already-active mirror dummy user should
         raise an AssertionError.