In Confluence use the Insert Markup featureset it to Markdown and add any CSS styles you want
for example:
<span style="background-color: #eee; border-top: 1px solid #aaa; border-bottom: 1px solid #aaa; font-family: monospace; padding: 2px;">
//path/to/folder/with/some_file.ext
</span>
easy copy+paste
<span style="background-color:#eee;border-top:1px solid #aaa;border-bottom:1px solid #aaa;font-family:monospace;padding:2px;">
</span>