It’s not possible to put text containing backtick characters into an inline code span in Legend.
According to Daring Fireball: Markdown Syntax Documentation:
To include a literal backtick character within a code span, you can use multiple backticks as the opening and closing delimiters:
``There is a literal backtick (`) here.``
which will produce this:
<p><code>There is a literal backtick (`) here.</code></p>
The backtick delimiters surrounding a code span may include spaces — one after the opening, one before the closing. This allows you to place literal backtick characters at the beginning or end of a code span…
It should render like this (which this forum software does correctly):
There is a literal backtick (`) here.
But none of this works in Legend: