feat: Add spoiler channel flag and functions

CHANGELOG.md

@@ -12,6 +12,9 @@ These changes are available on the `master` branch, but have not yet been releas
 
 ### Added
 
+- Added `ChannelFlags.is_spoiler_channel` and `.is_spoiler()` function to all applicable
+  channel types. ([#3252](https://github.com/Pycord-Development/pycord/pull/3252))
+
 ### Changed
 
 ### Fixed

discord/channel.py

@@ -312,6 +312,13 @@ def is_nsfw(self) -> bool:
         """Checks if the channel is NSFW."""
         return self.nsfw
 
+    def is_spoiler(self) -> bool:
+        """Checks if the channel is a spoiler channel.
+
+        .. versionadded:: 2.9
+        """
+        return self.flags.is_spoiler_channel
+
     @property
     def last_message(self) -> Message | None:
         """Fetches the last message from this channel in cache.
@@ -1810,6 +1817,13 @@ def is_nsfw(self) -> bool:
         """Checks if the channel is NSFW."""
         return self.nsfw
 
+    def is_spoiler(self) -> bool:
+        """Checks if the channel is a spoiler channel.
+
+        .. versionadded:: 2.9
+        """
+        return self.flags.is_spoiler_channel
+
     @property
     def last_message(self) -> Message | None:
         """Fetches the last message from this channel in cache.
@@ -2398,6 +2412,13 @@ def is_nsfw(self) -> bool:
         """Checks if the channel is NSFW."""
         return self.nsfw
 
+    def is_spoiler(self) -> bool:
+        """Checks if the channel is a spoiler channel.
+
+        .. versionadded:: 2.9
+        """
+        return self.flags.is_spoiler_channel
+
     @property
     def last_message(self) -> Message | None:
         """Fetches the last message from this channel in cache.

discord/flags.py

@@ -1586,6 +1586,14 @@ def hide_media_download_options(self):
         """
         return 1 << 15
 
+    @flag_value
+    def is_spoiler_channel(self):
+        """:class:`bool`: Returns ``True`` if the channel is a spoiler channel.
+
+        .. versionadded:: 2.9
+        """
+        return 1 << 21
+
 
 @fill_with_flags()
 class AttachmentFlags(BaseFlags):