Styled error messages

[Caylies]

Description

Some error messages aren't styled unlike others. All error messages should be styled to enhance DexI's appearance.

[ethanthopkins]

Hi, I'm new to the project. I can help with this. Can you please assign it to me?

[ethanthopkins]

I submitted a PR. I'm a new dev so let me know if anything else needs to be done with it :)

[Caylies]

Resolved by #9