Fix ambiguous_associated_items case

[rgiot]

Hello,

my enum looks like that:

#[derive(IntoPrimitive, TryFromPrimitive, Copy, Clone, PartialEq, Debug)]
#[repr(u8)]
pub enum BasicTokenNoPrefix {
    EndOfTokenisedLine = 0,
    StatementSeparator = 1,

    [...]
    Error,
    [...]
}

and I obtain this compilation error when using it:

error: ambiguous associated item
 --> src/basic/tokens.rs:7:10
  |
7 | #[derive(IntoPrimitive, TryFromPrimitive, Copy, Clone, PartialEq, Debug)]
  |          ^^^^^^^^^^^^^^^^
  |
  = note: #[deny(ambiguous_associated_items)] on by default
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #57644 <https://github.com/rust-lang/rust/issues/57644>
note: `Error` could refer to variant defined here
 --> src/basic/tokens.rs:145:5
  |
14|     Error,
  |     ^^^^^
note: `Error` could also refer to associated type defined here

This patch allows to fix this issue.

[illicitonion]

Thanks for the fix! I've just published 0.2.2 with this commit included :)