Add default functions to MouseReport, MediaKeyboardReport and SystemC…

…ontrolReport

It was already there for KeyboardReport where documentation is added to
the function

src/descriptor.rs

@@ -56,6 +56,19 @@ pub struct MouseReport {
     pub pan: i8,   // Scroll left (negative) or right (positive) this many units
 }
 
+impl MouseReport {
+    /// Create a new MouseReport with all fields set to zero.
+    pub const fn default() -> Self {
+        Self {
+            buttons: 0,
+            x: 0,
+            y: 0,
+            wheel: 0,
+            pan: 0,
+        }
+    }
+}
+
 /// KeyboardReport describes a report and its companion descriptor that can be
 /// used to send keyboard button presses to a host and receive the status of the
 /// keyboard LEDs.
@@ -84,6 +97,7 @@ pub struct KeyboardReport {
 }
 
 impl KeyboardReport {
+    /// Create a new KeyboardReport with all fields set to zero.
     pub const fn default() -> Self {
         Self {
             modifier: 0,
@@ -798,6 +812,13 @@ pub struct MediaKeyboardReport {
     pub usage_id: u16,
 }
 
+impl MediaKeyboardReport {
+    /// Create a new MediaKeyboardReport with all fields set to 0
+    pub const fn default() -> Self {
+        Self { usage_id: 0 }
+    }
+}
+
 /// Media player usage ids that can be used in MediaKeyboardReport
 #[non_exhaustive]
 #[repr(u16)]
@@ -875,6 +896,13 @@ pub struct SystemControlReport {
     pub usage_id: u8,
 }
 
+impl SystemControlReport {
+    /// Create a new SystemControlReport with all fields set to 0
+    pub const fn default() -> Self {
+        Self { usage_id: 0 }
+    }
+}
+
 /// System control usage ids to use with SystemControlReport
 #[non_exhaustive]
 #[repr(u8)]