Fix UpdateType by correcting values for 'bell' and 'clipboard'

[hjalves]

According to the RFB protocol, the current values for update types Bell (3) and ServerCutText/Clipboard (2) are mixed up. The correct values should be:

• 2: Bell
• 3: ServerCutText (Clipboard)

The current misalignment triggers an issue whenever there's a clipboard update in the X server. This misconfiguration leads to crashes within the library due to encountered exceptions arising from incorrect byte handling.