Docs fix spelling issues

[nnsW3]

Hello
I fixed several spelling issues.
Br, Elias.

[CLAassistant]

All committers have signed the CLA.

[macfarla]

Hi @nnsW3 - thanks for your interest in our project.
Hi, thanks for your interest in our project. We'd love for you to contribute code, however we don't accept trivial contributions such as this, to avoid adding load to our human reviewers and non-human CI. Have a look at good first issues, and please read our contributing guidelines https://github.com/Consensys/web3signer/blob/master/CONTRIBUTING.md#guidelines-for-non-code-and-other-trivial-contributions

If you'd like to, you can open an issue for the typos and we can fix them in a batch.