Add a trigger factory for isConnected on CommandGenericHID

Author: shueja

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/button/CommandGenericHID.java

@@ -322,4 +322,25 @@ public void setRumble(GenericHID.RumbleType type, double value) {
   public boolean isConnected() {
     return m_hid.isConnected();
   }
+
+
+  /**
+   * Constructs a Trigger instance that is true when the HID is connected, attached to then loop.
+   * @param loop the event loop instance to attach the Trigger to.
+   * @return a Trigger instance that is true when the HID is connected.
+   */
+  public Trigger connected(EventLoop loop) {
+    return m_isConnectedCache.computeIfAbsent(
+      k -> new Trigger(loop, this::isConnected)
+    );
+  }
+
+  /**
+   * Constructs a Trigger instance that is true when the HID is connected, attached to
+   * {@link CommandScheduler#getDefaultButtonLoop() the default command scheduler button loop}.
+   * @return a Trigger instance that is true when the HID is connected.
+   */
+  public Trigger connected() {
+    return connected(CommandScheduler.getInstance().getDefaultButtonLoop());
+  }
 }