Remove mention of old SVG text pref in comment; no bug. (DONTBUILD)

--HG--
extra : amend_source : 637d6f080ac7dab34f2129b5b339a5b79bda5899

layout/svg/SVGTextFrame.h

@@ -212,8 +212,7 @@ public:
 } // namespace mozilla
 
 /**
- * Frame class for SVG <text> elements, used when the
- * layout.svg.css-text.enabled is true.
+ * Frame class for SVG <text> elements.
  *
  * An SVGTextFrame manages SVG text layout, painting and interaction for
  * all descendent text content elements.  The frame tree will look like this: