Remove clippy warnings.

[martinfrances107]

I just want to fix a minor issue

I want to keep the main branch clear of clippy warnings -- just so when reviewing a PR any new warnings can be directly attributed to new code.

Current we have 2 warning of this form :-

I am about to create a PR to fix this.

warning: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
   --> geo-types/src/line_string.rs:174:5
    |
174 |     pub fn lines<'a>(&'a self) -> impl ExactSizeIterator + Iterator<Item = Line<T>> + 'a {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(clippy::needless_lifetimes)]` on by default
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes

[frewsxcv]

#631