[CodeCompletion] Negate incorrect comment NFC

Author: benlangmuir

lib/IDE/CodeCompletion.cpp

@@ -3807,7 +3807,7 @@ class CompletionOverrideLookup : public swift::VisibleDeclConsumer {
     bool hasIntroducer = hasFuncIntroducer || hasVarIntroducer;
 
     if (auto *FD = dyn_cast<FuncDecl>(D)) {
-      // We can override operators as members.
+      // We cannot override operators as members.
       if (FD->isBinaryOperator() || FD->isUnaryOperator())
         return;