It’s a little complicated. A USB-3 connection must provide higher current 900mA than a USB-2 connection 500mA. As such a USB-3 data connection can charge faster than a USB-2 connection - some people may call this “fast charging”.

However USB-PD (Power Delivery, aka fast charging) was released as part of the USB 3.1 specification, but it does not require a USB-3 data connection and neither does a USB-3 data connection require USB-PD. You can see all the different USB-C modes on Wikipedia as well, where USB-2 and Power Delivery are listed separately: https://en.wikipedia.org/wiki/USB-C#USB-C_receptacle_pin_usage_in_different_modes