Add option to change monospace font

[Guanran928]

Your use case

Add an option to change the monospace font used in code snippet messages.

Element Web is using Inconsolata for monospace texts, I want to use my system's monospace font for consistency.

It also does not match Inter's x-height very well, see https://github.com/element-hq/element-web/issues/15077:

Have you considered any alternatives?

No response

Additional context

Currently there an option for sans-serif texts, but not for monospaced texts.