WSUG: Fixed some typos.

This was reported by Emre Baris.

Change-Id: Ia37527e2a612fcbabd3ce7c6d8faf33905bbe52d
Reviewed-on: https://code.wireshark.org/review/4701
Reviewed-by: Stig Bjørlykke <stig@bjorlykke.org>