Reduce bottom-margin for code blocks within lists

Problem

Like for <p>, also 50% bottom margin for code blocks within lists:

Margin after <p>Code sample:</p> there is 12px, but margin after code block is 24px.

Other

I don't think there's need to support case with bottom margin of 0 because code blocks probably always exist within "open" lists - never in compact lists (would be weird).

Also check if there are any other elements that should be tuned for half the margin when they exist within lists (e.g. tables)?

Environment Info

• Python Version: 2.7
• Sphinx Version: 1.8.2
• RTD Theme Version: 0.4.2