Code style for text inputs in modals

[advaith1]

It would be useful if text inputs had a code style that enables a monospaced font and makes tab indent instead of opening keyboard nav, like the UI for writing a codeblock in the chat box. A language field to set for syntax highlighting would be ideal.

At WidgetBot we're using a text input for modifying custom CSS, but the plain text input is not great for it; with our old text command we have users type a ```css codeblock which has a great editing experience on desktop.

mockup: