Meme Remarkup code does not work in Phame

Reproduction Instructions
Complete steps which allow someone else who does not have access to your environment to reproduce the bug.

  1. Write a blog post containing a meme Remarkup code, for example {meme, src=nyancat, above=test, below=test}
  2. Notice the image rendered correctly in the preview below the editor.
  3. Publish the blog post.
  4. View the published blog post and notice the Remarkup code for the meme is shown instead of the image itself.

Phabricator/Arcanist Version
Output from Config > Version Information or arc version.

phabricator	ff6f24db2bc0	Feb 12 2020	2327578adc94
arcanist	729100955129	Jan 30 2020	21a1828ea06c
phutil	034cf7cc3994	Jan 30 2020	cc2a3dbf5903