suppress needless_lifetimes lints from clippy 0.1.83

[matt-phylum]

I think I did this correctly.

In Clippy 0.1.83, without the changes in expand.rs, the new test in test_lints.rs fails with the following output:

error: the following explicit lifetimes could be elided: 'a
  --> tests/test_lints.rs:29:22
   |
29 |     pub enum MyError<'a> {
   |                      ^^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
note: the lint level is defined here
  --> tests/test_lints.rs:25:13
   |
25 |     #![deny(clippy::needless_lifetimes)]
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: elide the lifetimes
   |
29 -     pub enum MyError<'a> {
29 +     pub enum MyError'_> {
   |

error: could not compile `thiserror` (test "test_lints") due to 1 previous error

Clippy doesn't like the generated impl From and gets confused about what it's fixing (rust-lang/rust-clippy#12789?) and the result is a confusing message suggesting code that is broken in multiple ways. The Display and Error impls don't seem to be affected, so this probably only affects users that use borrowed errors and #[from].

I encountered this in a project I can't share, but it's the same case as ruffle-rs/ruffle#18761 https://github.com/ruffle-rs/ruffle/blob/bd89e5b216769168d08548f01e2b6871280ab829/core/src/avm1/error.rs

[dtolnay]

Thanks!