fix typo in code example in C.43 (#2040)

CppCoreGuidelines.md

@@ -5603,7 +5603,7 @@ A default constructor often simplifies the task of defining a suitable [moved-fr
     };
 
     vector<Date> vd1(1000);   // default Date needed here
-    vector<Date> vd2(1000, Date{Month::October, 7, 1885});   // alternative
+    vector<Date> vd2(1000, Date{7, Month::October, 1885});   // alternative
 
 The default constructor is only auto-generated if there is no user-declared constructor, hence it's impossible to initialize the vector `vd1` in the example above.
 The absence of a default value can cause surprises for users and complicate its use, so if one can be reasonably defined, it should be.