There is no need to use double backticks. Also, insert extra newlines
between header and item, which paragraphs the item [1, 2], increading
readability by giving a little more "breathing" room between items. This
is also done in `macros.md`. Also, indentation of the definition block
should technically be 4 if extra paragraphs are needed, but it's better
to use 4 indentation always to prevent future problems after edits.
[1] https://python-markdown.github.io/extensions/definition_lists/
[2] https://michelf.ca/projects/php-markdown/extra/#def-list
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