Support Enter key of numpad on Windows

The yamatanooroti gem can't emulate numpad key pressing...

Author: aycabta

lib/reline/windows.rb

@@ -206,6 +206,8 @@ def self.process_key_event(repeat_count, virtual_key_code, virtual_scan_code, ch
         @@output_buf.push(0, 80)
       when VK_DELETE
         @@output_buf.push(0, 83)
+      when VK_RETURN
+        @@output_buf.push(char_code) # must be 0x0D
       end
     elsif char_code == 0 and control_key_state != 0
       # unknown