Ignore derive_partial_eq_without_eq clippy lint

    error: you are deriving `PartialEq` and can implement `Eq`
     --> src/expr.rs:9:14
      |
    9 |     #[derive(PartialEq)]
      |              ^^^^^^^^^ help: consider deriving `Eq` as well: `PartialEq, Eq`
      |
      = note: `-D clippy::derive-partial-eq-without-eq` implied by `-D clippy::all`
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derive_partial_eq_without_eq

    error: you are deriving `PartialEq` and can implement `Eq`
       --> src/lib.rs:130:23
        |
    130 | #[derive(Copy, Clone, PartialEq)]
        |                       ^^^^^^^^^ help: consider deriving `Eq` as well: `PartialEq, Eq`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derive_partial_eq_without_eq

src/lib.rs

@@ -108,6 +108,7 @@
 //! 4. Remove the computed number of spaces from the beginning of each line.
 
 #![allow(
+    clippy::derive_partial_eq_without_eq,
     clippy::module_name_repetitions,
     clippy::needless_doctest_main,
     clippy::needless_pass_by_value,