modules: fix Application and Context aliases for superprojects.

Oh well :(

modules/FindMagnum.cmake

@@ -616,7 +616,7 @@ find_package_handle_standard_args(Magnum
 if(_MAGNUM_WINDOWLESSAPPLICATION_ALIAS AND NOT TARGET Magnum::WindowlessApplication)
     get_target_property(_MAGNUM_WINDOWLESSAPPLICATION_ALIASED_TARGET ${_MAGNUM_WINDOWLESSAPPLICATION_ALIAS} ALIASED_TARGET)
     if(_MAGNUM_WINDOWLESSAPPLICATION_ALIASED_TARGET)
-        add_library(${_MAGNUM_WINDOWLESSAPPLICATION_ALIAS} ALIAS ${_MAGNUM_WINDOWLESSAPPLICATION_ALIASED_TARGET})
+        add_library(Magnum::WindowlessApplication ALIAS ${_MAGNUM_WINDOWLESSAPPLICATION_ALIASED_TARGET})
     else()
         add_library(Magnum::WindowlessApplication UNKNOWN IMPORTED)
         get_target_property(_MAGNUM_WINDOWLESSAPPLICATION_IMPORTED_CONFIGURATIONS ${_MAGNUM_WINDOWLESSAPPLICATION_ALIAS} IMPORTED_CONFIGURATIONS)
@@ -646,7 +646,7 @@ endif()
 if(_MAGNUM_APPLICATION_ALIAS AND NOT TARGET Magnum::Application)
     get_target_property(_MAGNUM_APPLICATION_ALIASED_TARGET ${_MAGNUM_APPLICATION_ALIAS} ALIASED_TARGET)
     if(_MAGNUM_APPLICATION_ALIASED_TARGET)
-        add_library(${_MAGNUM_APPLICATION_ALIAS} ALIAS ${_MAGNUM_APPLICATION_ALIASED_TARGET})
+        add_library(Magnum::Application ALIAS ${_MAGNUM_APPLICATION_ALIASED_TARGET})
     else()
         add_library(Magnum::Application UNKNOWN IMPORTED)
         get_target_property(_MAGNUM_APPLICATION_IMPORTED_CONFIGURATIONS ${_MAGNUM_APPLICATION_ALIAS} IMPORTED_CONFIGURATIONS)
@@ -676,7 +676,7 @@ endif()
 if(_MAGNUM_CONTEXT_ALIAS AND NOT TARGET Magnum::Context)
     get_target_property(_MAGNUM_CONTEXT_ALIASED_TARGET ${_MAGNUM_CONTEXT_ALIAS} ALIASED_TARGET)
     if(_MAGNUM_CONTEXT_ALIASED_TARGET)
-        add_library(${_MAGNUM_CONTEXT_ALIAS} ALIAS ${_MAGNUM_CONTEXT_ALIASED_TARGET})
+        add_library(Magnum::Context ALIAS ${_MAGNUM_CONTEXT_ALIASED_TARGET})
     else()
         add_library(Magnum::Context UNKNOWN IMPORTED)
         get_target_property(_MAGNUM_CONTEXT_IMPORTED_CONFIGURATIONS ${_MAGNUM_CONTEXT_ALIAS} IMPORTED_CONFIGURATIONS)