I strongly recommend not putting raw HTML in an outputText element. I've seen problems come from that approach, and not only on the JSF platform. A more JSF-friendly (if less terse) solution for panelGrid and table cells looks like this:
Actually, use of the <em> tag even in non-JSF HTML in this day and age will get you abused by some people. CSS is the preferred mechanism now.
However, if you absolutely insist on using raw HTML in an outputText, the proper attribute name isn't "escapeHTML", it's simply "escape".
An IDE is no substitute for an Intelligent Developer.