All you have to do is select the field you want to display as link and then change the code from:
<xsl:value-of select="@VariableName" display-output-escaping="yes"></xsl:value-of>
This works in SharePoint 2010, if you’re on 2013 you should use the following (notice the closing tag):
<xsl:value-of select="@AssignedTo" disable-output-escaping="yes" />
Thanks to Ryan Tate for pointing it out.
[…] issue today at work. I came across multiple blog posts detailing the issue including this one and this other but unfortunately the code mentioned in both places threw an error in SharePoint […]