[documentation] WiFi.begin() also accepts bssid, not documented

[atesin]

hi... i was browsing the source... documentation in README.md doesn't mention WiFi.begin()also accept bssid as optional parameter... this differs with WiFiNINA api that doesn't support bssid

WiFiEspAT/src/WiFi.h

Line 72 in b9443b2

int begin(const char* ssid = nullptr, const char *passphrase = nullptr, const uint8_t* bssid = nullptr);

documentation: https://github.com/JAndrassy/WiFiEspAT/blob/master/README.md#enhanced-wifi-api

WiFiEspAT/README.md

Line 193 in b9443b2

* `begin` for AT 1.7 begin() without parameters (joining remembered WiFi) is not available

WiFiNINA api: https://www.arduino.cc/reference/en/libraries/wifinina/wifi.begin/

Syntax
WiFi.begin(ssid);
WiFi.begin(ssid, pass);
WiFi.begin(ssid, keyIndex, key);