[CodeHealth] Use Position::anchorNode instead of deprecatedNode.

Source/core/editing/BreakBlockquoteCommand.cpp

Index: Source/core/editing/BreakBlockquoteCommand.cpp
diff --git a/Source/core/editing/BreakBlockquoteCommand.cpp b/Source/core/editing/BreakBlockquoteCommand.cpp
index c77dd2a7974e5d64e78d6200ef3e106ebb008339..3b44e672b39b99134968f11c02a1bda960660ae7 100644
--- a/Source/core/editing/BreakBlockquoteCommand.cpp
+++ b/Source/core/editing/BreakBlockquoteCommand.cpp
@@ -106,7 +106,7 @@ void BreakBlockquoteCommand::doApply()
         pos = pos.previous();
 
     // startNode is the first node that we need to move to the new blockquote.
-    Node* startNode = pos.deprecatedNode();
+    Node* startNode = pos.anchorNode();
     ASSERT(startNode);
 
     // Split at pos if in the middle of a text node.