Bug 1581523: part 2) Remove outdated comment in `HTMLTextAreaElement`. r=jorgk

Differential Revision: https://phabricator.services.mozilla.com/D46127

--HG--
extra : moz-landing-system : lando

dom/html/HTMLTextAreaElement.cpp

@@ -1046,7 +1046,6 @@ HTMLTextAreaElement::GetCols() { return Cols(); }
 
 NS_IMETHODIMP_(int32_t)
 HTMLTextAreaElement::GetWrapCols() {
-  // wrap=off means -1 for wrap width no matter what cols is
   nsHTMLTextWrap wrapProp;
   nsITextControlElement::GetWrapPropertyEnum(this, wrapProp);
   if (wrapProp == nsITextControlElement::eHTMLTextWrap_Off) {