feat: api v9 and threads (#5570)

Co-authored-by: Noel <icrawltogo@gmail.com>
Co-authored-by: Amish Shah <dev@shah.gg>
Co-authored-by: Vlad Frangu <kingdgrizzle@gmail.com>
Co-authored-by: SynthGhost <60333233+synthghost@users.noreply.github.com>
Co-authored-by: SpaceEEC <24881032+SpaceEEC@users.noreply.github.com>
Co-authored-by: Elliot <elliot@maisl.fr>
Co-authored-by: Antonio Román <kyradiscord@gmail.com>
Co-authored-by: Sugden <28943913+NotSugden@users.noreply.github.com>

src/util/MessageFlags.js

@@ -28,6 +28,7 @@ class MessageFlags extends BitField {}
  * * `SUPPRESS_EMBEDS`
  * * `SOURCE_MESSAGE_DELETED`
  * * `URGENT`
+ * * `HAS_THREAD`
  * * `EPHEMERAL`
  * * `LOADING`
  * @type {Object}
@@ -39,6 +40,7 @@ MessageFlags.FLAGS = {
   SUPPRESS_EMBEDS: 1 << 2,
   SOURCE_MESSAGE_DELETED: 1 << 3,
   URGENT: 1 << 4,
+  HAS_THREAD: 1 << 5,
   EPHEMERAL: 1 << 6,
   LOADING: 1 << 7,
 };