Appease clippy and add to CI

[Property404]

Seems like Clippy hasn't been run

[Samyak2]

Thank you for this! I was planning to address clippy at some point, but I appreciate this.

Looks like one clippy hint was missed (or deliberately ignored for the sake of not breaking the API?):

warning: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices
   --> src/tui.rs:345:44
    |
345 |     pub fn display_words(&mut self, words: &Vec<String>) -> MaybeError<Vec<Text>> {
    |                                            ^^^^^^^^^^^^ help: change this to: `&[String]`
    |
    = note: `#[warn(clippy::ptr_arg)]` on by default
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

Also, what do you think about adding clippy as step in CI?

[Samyak2]

Thanks a lot for contributing!