Much nicer looking error and warning messages

[emilk]

What

• Closes Improve visuals of error messages #8091

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[Wumpf]

This is so pretty! <3

Not fond of the selection color here. Maybe a brighter red instead?

[emilk]

[gavrelina]

Adding some ui nits:

colors (mostly!) are from the json color alias file
figma link

[Wumpf]

@emilk ⬆️ ⬆️ ⬆️ :)