docs: add rustdoc comments

src/close.rs

@@ -1,14 +1,20 @@
+//! Subscription close request parsing
 use crate::error::{Error, Result};
 use serde::{Deserialize, Serialize};
 
+/// Close command in network format
 #[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
 pub struct CloseCmd {
+    /// Protocol command, expected to always be "CLOSE".
     cmd: String,
+    /// The subscription identifier being closed.
     id: String,
 }
 
+/// Close command parsed
 #[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
 pub struct Close {
+    /// The subscription identifier being closed.
     pub id: String,
 }
 
@@ -22,9 +28,3 @@ impl From<CloseCmd> for Result<Close> {
         }
     }
 }
-
-impl Close {
-    pub fn get_id(&self) -> String {
-        self.id.clone()
-    }
-}