[turbofan] Improve a comment

Change-Id: I4ddb49bb4cb2cda52247354c53386369ad0e0844
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1817610Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63931}

src/compiler/node.h

@@ -149,7 +149,7 @@ class V8_EXPORT_PRIVATE Node final {
 
   Uses uses() { return Uses(this); }
 
-  // Returns true if {owner} is the user of {this} node.
+  // Returns true if {owner} is the only user of {this} node.
   bool OwnedBy(Node* owner) const {
     return first_use_ && first_use_->from() == owner && !first_use_->next;
   }