Add Meta+x shortcut for CUT

Add a scrcpy shortcut to send the CUT keycode.

README.md

@@ -583,6 +583,7 @@ _`Meta` is typically the `Windows` key on the keyboard, or `Cmd` on macOS._
  | Expand notification panel                            | `Meta`+`n`
  | Collapse notification panel                          | `Meta`+`Shift`+`n`
  | Press COPY³, then Copy device clipboard to computer  | `Meta`+`c`
+ | Press CUT³                                           | `Meta`+`x`
  | Paste computer clipboard to device                   | `Meta`+`v`
  | Copy computer clipboard to device, then press PASTE³ | `Meta`+`Shift`+`v`
  | Enable/disable FPS counter (on stdout)               | `Meta`+`i`