Added bad/good example for C.89, closes #1727

CppCoreGuidelines.md

@@ -6513,11 +6513,11 @@ The alternative is to make two failure states compare equal and any valid state
 
 ##### Note
 
-This rule applies to all the usual comparison operators: `!=`, `<`, `<=`, `>`, and `>=`.
+This rule applies to all the usual comparison operators: `!=`, `<`, `<=`, `>`, `>=`, and `<=>`.
 
 ##### Enforcement
 
-* Flag an `operator==()` for which the argument types differ; same for other comparison operators: `!=`, `<`, `<=`, `>`, and `>=`.
+* Flag an `operator==()` for which the argument types differ; same for other comparison operators: `!=`, `<`, `<=`, `>`, `>=`, and `<=>`.
 * Flag member `operator==()`s; same for other comparison operators: `!=`, `<`, `<=`, `>`, and `>=`.
 
 ### <a name="Rc-eq-base"></a>C.87: Beware of `==` on base classes
@@ -6562,11 +6562,11 @@ Of course there are ways of making `==` work in a hierarchy, but the naive appro
 
 ##### Note
 
-This rule applies to all the usual comparison operators: `!=`, `<`, `<=`, `>`, `>=`, and `<=>`.
+This rule applies to all the usual comparison operators: `!=`, `<`, `<=`, `>`, and `>=`.
 
 ##### Enforcement
 
-* Flag a virtual `operator==()`; same for other comparison operators: `!=`, `<`, `<=`, `>`, `>=`, and `<=>`.
+* Flag a virtual `operator==()`; same for other comparison operators: `!=`, `<`, `<=`, `>`, and `>=`.
 
 ### <a name="Rc-hash"></a>C.89: Make a `hash` `noexcept`
 
@@ -19414,6 +19414,22 @@ It is almost always a bug to mention an unnamed namespace in a header file.
 Nothing external can depend on an entity in a nested unnamed namespace.
 Consider putting every definition in an implementation source file in an unnamed namespace unless that is defining an "external/exported" entity.
 
+##### Example; bad
+
+    static int f();
+    int g();
+    static bool h();
+    int k();
+
+##### Example; good
+
+    namespace {
+        int f();
+        bool h();
+    }
+    int g();
+    int k();
+
 ##### Example
 
 An API class and its members can't live in an unnamed namespace; but any "helper" class or function that is defined in an implementation source file should be at an unnamed namespace scope.