add Enum Info Provider

[plastikfan]

func NewEnumProvider[E ~int](acceptables map[E][]string) *assistant.EnumInfo[E] {
    return assistant.NewEnumInfo(acceptables)
}

type EnumProvider[E ~int] struct {
    Info *assistant.EnumInfo[E]
}

func (ep *EnumProvider[E]) NewValue() assistant.EnumValue[E] {
    return ep.Info.NewValue()
}