#1045 Fix reference to narrow_cast (#1046)

CppCoreGuidelines.md

@@ -11632,7 +11632,7 @@ A key example is basic narrowing:
 
 ##### Note
 
-The guideline support library offers a `narrow` operation for specifying that narrowing is acceptable and a `narrow` ("narrow if") that throws an exception if a narrowing would throw away information:
+The guideline support library offers a `narrow_cast` operation for specifying that narrowing is acceptable and a `narrow` ("narrow if") that throws an exception if a narrowing would throw away information:
 
     i = narrow_cast<int>(d);   // OK (you asked for it): narrowing: i becomes 7
     i = narrow<int>(d);        // OK: throws narrowing_error