docs: add rustdoc comments to all module options

This part of an upcoming effort to generate documentation from code.

Pushing this out before that stage so that the JSON schema is fully documented.

src/modules/music/config.rs

@@ -6,34 +6,50 @@ use std::path::PathBuf;
 #[derive(Debug, Deserialize, Clone)]
 pub struct Icons {
     /// Icon to display when playing.
+    ///
+    /// **Default**: ``
     #[serde(default = "default_icon_play")]
     pub(crate) play: String,
 
     /// Icon to display when paused.
+    ///
+    /// **Default**: ``
     #[serde(default = "default_icon_pause")]
     pub(crate) pause: String,
 
     /// Icon to display for previous button.
+    ///
+    /// **Default**: `󰒮`
     #[serde(default = "default_icon_prev")]
     pub(crate) prev: String,
 
     /// Icon to display for next button.
+    ///
+    /// **Default**: `󰒭`
     #[serde(default = "default_icon_next")]
     pub(crate) next: String,
 
-    /// Icon to display under volume slider
+    /// Icon to display under volume slider.
+    ///
+    /// **Default**: `󰕾`
     #[serde(default = "default_icon_volume")]
     pub(crate) volume: String,
 
-    /// Icon to display nex to track title
+    /// Icon to display nex to track title.
+    ///
+    /// **Default**: `󰎈`
     #[serde(default = "default_icon_track")]
     pub(crate) track: String,
 
-    /// Icon to display nex to album name
+    /// Icon to display nex to album name.
+    ///
+    /// **Default**: `󰀥`
     #[serde(default = "default_icon_album")]
     pub(crate) album: String,
 
-    /// Icon to display nex to artist name
+    /// Icon to display nex to artist name.
+    ///
+    /// **Default**: `󰠃`
     #[serde(default = "default_icon_artist")]
     pub(crate) artist: String,
 }
@@ -73,33 +89,62 @@ pub struct MusicModule {
     pub(crate) player_type: PlayerType,
 
     /// Format of current song info to display on the bar.
+    ///
+    /// Info on formatting tokens [below](#formatting-tokens).
+    ///
+    /// **Default**: `{title} / {artist}`
     #[serde(default = "default_format")]
     pub(crate) format: String,
 
-    /// Player state icons
+    /// Player state icons.
+    ///
+    /// See [icons](#icons).
     #[serde(default)]
     pub(crate) icons: Icons,
 
-    // -- MPD --
-    /// TCP or Unix socket address.
-    #[serde(default = "default_socket")]
-    pub(crate) host: String,
-    /// Path to root of music directory.
-    #[serde(default = "default_music_dir")]
-    pub(crate) music_dir: PathBuf,
-
+    /// Whether to show the play/pause status icon
+    /// on the bar.
+    ///
+    /// **Default**: `true`
     #[serde(default = "crate::config::default_true")]
     pub(crate) show_status_icon: bool,
 
+    /// Size to render the icons at, in pixels (image icons only).
+    ///
+    /// **Default** `32`
     #[serde(default = "default_icon_size")]
     pub(crate) icon_size: i32,
 
+    /// Size to render the album art image at inside the popup, in pixels.
+    ///
+    /// **Default**: `128`
     #[serde(default = "default_cover_image_size")]
     pub(crate) cover_image_size: i32,
 
+    // -- MPD --
+    /// *[MPD Only]*
+    /// TCP or Unix socket address of the MPD server.
+    /// For TCP, this should include the port number.
+    ///
+    /// **Default**: `localhost:6600`
+    #[serde(default = "default_socket")]
+    pub(crate) host: String,
+
+    /// *[MPD Only]*
+    /// Path to root of the MPD server's music directory.
+    /// This is required for displaying album art.
+    ///
+    /// **Default**: `$HOME/Music`
+    #[serde(default = "default_music_dir")]
+    pub(crate) music_dir: PathBuf,
+
     // -- Common --
+    /// See [truncate options](module-level-options#truncate-mode).
+    ///
+    /// **Default**: `null`
     pub(crate) truncate: Option<TruncateMode>,
 
+    /// See [common options](module-level-options#common-options).
     #[serde(flatten)]
     pub common: Option<CommonConfig>,
 }