EnumString: also impl From<&str>

[mirsella]

hello

https://docs.rs/strum/latest/strum/derive.EnumString.html implement FromStr and TryFrom<&str>, but not From<&str>.
its useful if are sure of the validity of the str, and want better ergonomics

thanks

[Peternator7]

Fixed in #476

[Peternator7]

This is available in 0.28