Paragraph: Markdown paragraph improvements

[penx]

Originally from a TODO adding in #276 and #333

• Add test for supporting text (added here, not sure what was meant here, @Loque- ?)
• Review code snippet styling
• Remove magic numbers from inline code styling blocks (added here) (not sure what this means, do you think you meant colour hexes @Loque- ?)

Also see #503 #223