Add note about legacy 802.11b rates (#138)

* Add note about legacy 802.11b rates

Found this on https://gbatemp.net/threads/wii-wont-connect-to-wifi.557433/#post-8936892 and changing my OpenWrt 2.4Ghz channel to enable legacy 802.11b rates fixed my Wii being unable to connect to LAN exactly as described in the thread.

* Update faq.md

docs/faq.md

@@ -134,6 +134,7 @@ The Wii's wireless networking hardware supports the maximum standard of 802.11g
 
 + APs enforcing WPA enterprise encryption, or WPA3 only
 + APs not backwards compatible with WiFi 3, or broadcasting only on the 5 GHz band
++ APs not supporting legacy 802.11b or 802.11g rates (i.e. APs supporting only 802.11n)
 
 ISPs known to provide routers incompatible with these settings:
 
@@ -147,4 +148,4 @@ If your ISP will not let you change these settings, or your current networking h
 + You can use a LAN adapter. It must have the `ASIX AX88772` chipset or say “compatible with Wii”. Here is a [recommended LAN adapter by uGreen](https://a.co/d/3OcSJDS).
 + Alternatively, you can buy a secondary router and continue to use the network you already have, like a mesh. Any cheap router meeting the above standards (such as the Linksys WRT54G) will work.
 
-For the Wii U, vWii uses the internet settings set in the Wii U's main settings, but can be optionally separated with the `Wii VC Launch` Aroma plugin.
+For the Wii U, vWii uses the internet settings set in the Wii U's main settings, but can be optionally separated with the `Wii VC Launch` Aroma plugin.