While wireless and Wi-Fi do not mean the same (one could reasonably consider wireless as a hypernym of Wi-Fi), they are often used as synonyms. This poses a certain problem for our emerging taxonomy.
I'd prefer the second option for two reasons. We would not need to edit every post where someone uses WiFi as synonym for anything wireless and falling back on a hypernym never makes the tagging incorrect. Secondly, a specific 802.11 tag will only be used by people who actually thought about the technology and want to focus on that aspect.