exceptions: Update translated errors for stream to channel rename.

In zerver/lib/exceptions.py, updates translated error strings
to use channel instead of stream.

Note that the STREAM_WILDCARD_MENTION_NOT_ALLOWED and the
STREAM_DOES_NOT_EXIST error codes, and any additional fields
included with those errors, are not changed in these updates.

Part of stream to channel rename project.

zerver/lib/exceptions.py

@@ -174,7 +174,7 @@ class StreamDoesNotExistError(JsonableError):
     @staticmethod
     @override
     def msg_format() -> str:
-        return _("Stream '{stream}' does not exist")
+        return _("Channel '{stream}' does not exist")
 
 
 class StreamWithIDDoesNotExistError(JsonableError):
@@ -187,7 +187,7 @@ class StreamWithIDDoesNotExistError(JsonableError):
     @staticmethod
     @override
     def msg_format() -> str:
-        return _("Stream with ID '{stream_id}' does not exist")
+        return _("Channel with ID '{stream_id}' does not exist")
 
 
 class CannotDeactivateLastUserError(JsonableError):
@@ -631,7 +631,7 @@ class StreamWildcardMentionNotAllowedError(JsonableError):
     @staticmethod
     @override
     def msg_format() -> str:
-        return _("You do not have permission to use stream wildcard mentions in this stream.")
+        return _("You do not have permission to use channel wildcard mentions in this channel.")
 
 
 class TopicWildcardMentionNotAllowedError(JsonableError):

zerver/openapi/zulip.yaml

@@ -6653,7 +6653,7 @@ paths:
                       - example:
                           {
                             "result": "error",
-                            "msg": "You do not have permission to use stream wildcard mentions in this stream.",
+                            "msg": "You do not have permission to use channel wildcard mentions in this channel.",
                             "code": "STREAM_WILDCARD_MENTION_NOT_ALLOWED",
                           }
                         description: |
@@ -8010,7 +8010,7 @@ paths:
                       - example:
                           {
                             "result": "error",
-                            "msg": "You do not have permission to use stream wildcard mentions in this stream.",
+                            "msg": "You do not have permission to use channel wildcard mentions in this channel.",
                             "code": "STREAM_WILDCARD_MENTION_NOT_ALLOWED",
                           }
                         description: |
@@ -21300,9 +21300,9 @@ components:
           example:
             {
               "code": "STREAM_DOES_NOT_EXIST",
-              "msg": "Stream 'nonexistent_stream' does not exist",
+              "msg": "Channel 'nonexistent' does not exist",
               "result": "error",
-              "stream": "nonexistent_stream",
+              "stream": "nonexistent",
             }
     NonExistingStreamIdError:
       allOf:
@@ -21319,7 +21319,7 @@ components:
           example:
             {
               "code": "STREAM_DOES_NOT_EXIST",
-              "msg": "Stream with ID '9' does not exist",
+              "msg": "Channel with ID '9' does not exist",
               "result": "error",
               "stream_id": 9,
             }

zerver/tests/test_message_edit.py

@@ -1423,7 +1423,7 @@ class EditMessageTest(ZulipTestCase):
                 },
             )
         self.assert_json_error(
-            result, "You do not have permission to use stream wildcard mentions in this stream."
+            result, "You do not have permission to use channel wildcard mentions in this channel."
         )
 
         with mock.patch("zerver.lib.message.num_subscribers_for_stream_id", return_value=14):

zerver/tests/test_message_send.py

@@ -135,7 +135,7 @@ class MessagePOSTTest(ZulipTestCase):
                 "topic": "Test topic for stream ID message",
             },
         )
-        self.assert_json_error(result, "Stream with ID '99999' does not exist")
+        self.assert_json_error(result, "Channel with ID '99999' does not exist")
 
         msg = self.get_last_message()
         expected = (
@@ -558,7 +558,7 @@ class MessagePOSTTest(ZulipTestCase):
                 "topic": "Test topic",
             },
         )
-        self.assert_json_error(result, "Stream 'nonexistent_stream' does not exist")
+        self.assert_json_error(result, "Channel 'nonexistent_stream' does not exist")
 
     def test_message_to_nonexistent_stream_with_bad_characters(self) -> None:
         """
@@ -576,7 +576,7 @@ class MessagePOSTTest(ZulipTestCase):
             },
         )
         self.assert_json_error(
-            result, "Stream '&<"'><non-existent>' does not exist"
+            result, "Channel '&<"'><non-existent>' does not exist"
         )
 
     def test_message_to_stream_with_automatically_change_visibility_policy(self) -> None:
@@ -1961,7 +1961,7 @@ class StreamMessagesTest(ZulipTestCase):
             else:
                 with self.assertRaisesRegex(
                     JsonableError,
-                    "You do not have permission to use stream wildcard mentions in this stream.",
+                    "You do not have permission to use channel wildcard mentions in this channel.",
                 ):
                     self.send_stream_message(sender, "test_stream", content)