Allow special characters in WiFi SSID

[BitcoinPuritan]

Receiving an error when connecting to WiFi with an apostrophe in the SSID:
“RPC ERROR: WiFi Internal Error SSID may not have special characters”

[MattDHill]

Fixed in #3375 — StartOS was rejecting any non-ASCII character in a WiFi SSID (the is_ascii() guard). 802.11 allows an SSID to be arbitrary octets, so this was overly strict.

Note this validation was identical in 0.3.5.1 and 0.4.0, so it wasn't version-specific; the fix ships in 0.4.0.

A plain straight apostrophe (') was actually already accepted — your error implies a typographic apostrophe ('), which a phone keyboard often auto-substitutes. Either way, non-ASCII SSIDs are now allowed.