Analyzer feedback modal overflowing horizontally when feedback includes a <pre> element

Analyzer feedback modal is overflowing horizontally when feedback includes a <pre> element. See screenshot. To reproduce this yourself, you can submit any Elixir exercise with an unused variable. That will cause the analyzer feedback to have a <pre> element.

It would be cool if the width of the <pre> element was limited to only be as wide as the modal, and the scrollbar was on the <pre> element only, not on the whole modal.

Cc @dem4ron