Add `crate_path` option to `EnumInfo`

[ifiokjr]

Description

Add a crate_path option to the EnumInfo struct to allow patterns where other crates can reexport num_enum and allow consumers of their library to consume the From* macros without a direct dependency on the num_enum crate.

num_enum/num_enum_derive/src/parsing.rs

Lines 13 to 18 in 7138fc6

	pub(crate) struct EnumInfo {
	pub(crate) name: Ident,
	pub(crate) repr: Ident,
	pub(crate) variants: Vec<VariantInfo>,
	pub(crate) error_type_info: ErrorType,
	}

I'm happy to open a PR if this is something you're happy to use.

Example

use other_crate::num_num::IntoPrimitive;
use other_crate::num_num::TryFromPrimitive;

#[repr(u32)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, IntoPrimitive, TryFromPrimitive)]
#[num_enum(crate_path = ::other_crate::num_enum)]
pub enum MyEnum {
  A = 0,
  B = 1,
  C = 2,
}

[ifiokjr]

Closing this in favour of #76 and PR #77.