T1.2.1: Add rustdoc on MediaType variants and methods

crates/wzp-proto/src/media_type.rs

@@ -1,20 +1,26 @@
 use serde::{Deserialize, Serialize};
 
-/// Media stream type carried in a v2 [`MediaHeader`](crate::MediaHeaderV2).
+/// Media stream type carried in a v2 [`MediaHeaderV2`](crate::MediaHeaderV2).
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[repr(u8)]
 pub enum MediaType {
+    /// Encoded speech / music (Opus, Codec2, ComfortNoise).
     Audio = 0,
+    /// Encoded video access unit (H.264, H.265, AV1; PRD-video-multicodec).
     Video = 1,
+    /// Opaque payload not interpreted by the relay (reserved).
     Data = 2,
+    /// In-band control message carried on the media plane (reserved).
     Control = 3,
 }
 
 impl MediaType {
+    /// Encode to the wire byte representation (`self as u8`).
     pub const fn to_wire(self) -> u8 {
         self as u8
     }
 
+    /// Decode from a wire byte. Returns `None` for values outside 0..=3.
     pub const fn from_wire(v: u8) -> Option<Self> {
         match v {
             0 => Some(Self::Audio),