Bug 1725930 - Make `TextServicesDocument::HasSameBlockNodeParent` refer 2nd text node as expected r=m_kato

This is just a simple mistake, but I'm not sure how this break the callers.
Therefore, I don't have a testcase for this.

Differential Revision: https://phabricator.services.mozilla.com/D122705

editor/spellchecker/TextServicesDocument.cpp

@@ -1590,7 +1590,7 @@ void TextServicesDocument::ClearDidSkip(
 bool TextServicesDocument::HasSameBlockNodeParent(Text& aTextNode1,
                                                   Text& aTextNode2) {
   nsIContent* container1 = aTextNode1.GetParent();
-  nsIContent* container2 = aTextNode1.GetParent();
+  nsIContent* container2 = aTextNode2.GetParent();
 
   if (container1 == container2) {
     return true;