because the CSS hastext-align: justify; on the text, and inline code is a<code> tag with a bunch of<pre> tags,

<codeclass="docutils literal notranslate"><spanclass="pre">set('abc')</span><spanclass="pre">==</span><spanclass="pre">frozenset('abc')</span></code>

the spaces between the<pre> tags get expanded:

https://docs.python.org/3/library/stdtypes.html#frozenset.copy