Incorrectly trims whitespace

[kitsonk]

Source:

`` Edit post `slug-here` ``

Expected:

`` Edit post `slug-here` ``

Which gets rendered as:

<p><code>Edit post `slug-here`</code></p>

Actual:

``Edit post `slug-here` ``

Which gets rendered as:

<p><code>Edit post `slug-here` </code></p>

Which contains a trailing whitespace in a code block, which then looks incorrect when displayed.

Ref: denoland/deno#10313