Make it discoverable that Debug etc is brought into the Magnum namespace.

doc/changelog.dox

@@ -648,6 +648,11 @@ See also:
     @ref platforms-windows "Windows platform docs" (see [mosra/magnum#227](https://github.com/mosra/magnum/issues/227) and
     [mosra/magnum#439](https://github.com/mosra/magnum/issues/439))
 -   Various documentation fixes (see [mosra/magnum#492](https://github.com/mosra/magnum/issues/492))
+-   @ref Corrade::Utility::Debug and friends were always brought to the )
+    @ref Magnum namespace via a @cpp using @ce directive, but this was never
+    reflected in the docs and thus hidden from users. Now it's shown in the
+    docs as a set of @ref Debug etc typedefs instead, to make them more
+    discoverable.
 
 @section changelog-2020-06 2020.06
 

src/Magnum/Magnum.h

@@ -43,11 +43,47 @@ namespace Magnum {
 /* Bring whole Corrade namespace */
 using namespace Corrade;
 
-/* Bring debugging facility from Corrade::Utility namespace */
+#ifdef DOXYGEN_GENERATING_OUTPUT
+/**
+@brief Alias for debug output
+
+A shorthand for the fully-qualified name in Corrade.
+@see @ref Warning, @ref Error, @ref Fatal,
+    @ref Corrade::TestSuite::Tester::Debug
+*/
+typedef Corrade::Utility::Debug Debug;
+
+/**
+@brief Alias for warning output
+
+A shorthand for the fully-qualified name in Corrade.
+@see @ref Debug, @ref Error, @ref Fatal,
+    @ref Corrade::TestSuite::Tester::Warning
+*/
+typedef Corrade::Utility::Warning Warning;
+
+/**
+@brief Alias for error output
+
+A shorthand for the fully-qualified name in Corrade.
+@see @ref Debug, @ref Warning, @ref Fatal,
+    @ref Corrade::TestSuite::Tester::Error
+*/
+typedef Corrade::Utility::Error Error;
+
+/**
+@brief Alias for fatal output
+
+A shorthand for the fully-qualified name in Corrade.
+@see @ref Debug, @ref Warning, @ref Error
+*/
+typedef Corrade::Utility::Fatal Fatal;
+#else
 using Corrade::Utility::Debug;
 using Corrade::Utility::Warning;
 using Corrade::Utility::Error;
 using Corrade::Utility::Fatal;
+#endif
 
 #ifdef DOXYGEN_GENERATING_OUTPUT
 /**