Fix for rare monofont element computed font-size, and progress max-width

What's Changed

• feat(default): max-width for <progress>
• refactor(develop): rm text-decoration inherit, before/after. Inheritance of text-decoration for ::before, ::after seems to
  already be preserved, and is not a catch all since text-decoration
  is shorthand.
• fix(default): add fix for rare monospace font-size gotcha with the classic code, kbd, samp, pre { font-family: monospace, monospace; }

For not documented files:

• feat(other): extra var --space-block
• feat(other): add prose-book css class file

Full Changelog: v0.4.0...v0.4.1