Diagnostics should render markdown correctly

[everdrone]

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• [X] Completed

Describe the bug / provide steps to reproduce it

Hovering on rustc diagnostics should correctly render markdown (specifically inline code marked by backticks)

Environment

Zed: v0.150.0 (Zed Dev f7f5a255845b45ac33ab88bfdc023894034168b7) OS: Windows 10.0.22631 Memory: 63.1 GiB Architecture: x86_64 GPU: NVIDIA GeForce RTX 4090 || NVIDIA || 560.81

If applicable, add mockups / screenshots to help explain present your vision of the feature

See how 'static and #[warn(static_mut_refs)] are rendered using the sans ui font, not the buffer monospace font

If applicable, attach your Zed.log file to this issue.

Zed.log