[docs]: property `isEnabled` misnamed as `enabled`

[AdamRaichu]

In the code, there is a property called isEnabled.

https://github.com/1ForeverHD/TopbarPlus/blob/bd33b850b87ab7a71a518fb22110c44e42b812f4/src/Icon/init.lua#L229

However, in the docs, it is referred to as enabled.

https://1foreverhd.github.io/TopbarPlus/api/#enabled