Use a monospaced font for Wiki editor
Description
The current textarea for editing project spaces uses a proportional font. While this makes sense for general text editing, it is rather annoying when working with Markdown, especially when editing tables and blocks of code. I always tend to change it myself via the inspector, but that obviously resets with every page reload.
Proposal
Change to font used in the Wiki editor to a monospaced font, or add an option to enable a monospaced font when there is a good reason to have a proportional font. The same could also applies to the textarea used for issues and merge requests when people see a demand for it.