Clarify comments for methods added in r178921

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index dc44eb7ec4660f037339855976e4169f8b3c264a..412cc3af9934731bd65ad6b62bd5ecbe04d44e67 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -1073,9 +1073,9 @@ private:
     friend class Node;
     friend class IgnoreDestructiveWriteCountIncrementer;
 
-    bool isDocumentFragment() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
-    bool isDocumentNode() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
-    bool isElementNode() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
+    bool isDocumentFragment() const WTF_DELETED_FUNCTION; // This will catch anyone doing an unnecessary check.
+    bool isDocumentNode() const WTF_DELETED_FUNCTION; // This will catch anyone doing an unnecessary check.
+    bool isElementNode() const WTF_DELETED_FUNCTION; // This will catch anyone doing an unnecessary check.
 
     ScriptedAnimationController& ensureScriptedAnimationController();
     virtual SecurityContext& securityContext() OVERRIDE FINAL { return *this; }