Spelling fixes

[Ivordir]

Fixes a typo in the README and makes other spelling corrections in the documentation.

[Ivordir]

Btw, I used https://github.com/crate-ci/typos to find these spelling mistakes.

[Ogeon]

Oh, neat! I usually run an in-editor spell checker, but mistakes still happen. 🙂

[Ogeon]

But, thank you! With the intentionally misspelled word back where it belongs, I think this is good to go.

bors r+

[bors[bot]]

Build succeeded:

• ci