Audio: remove useless deprecated function.

The std::vector overload is enough. I removed it everywhere else but not
here? Was I drunk or what.

src/Magnum/Audio/Source.h

@@ -450,12 +450,6 @@ class MAGNUM_AUDIO_EXPORT Source {
         static void rewind(const std::vector<std::reference_wrapper<Source>>& sources); /**< @overload */
 
         #ifdef MAGNUM_BUILD_DEPRECATED
-        /**
-         * @copybrief rewind(std::initializer_list<std::reference_wrapper<Source>>)
-         * @deprecated Use @ref Magnum::Audio::Source::rewind(std::initializer_list<std::reference_wrapper<Source>>) "rewind(std::initializer_list<std::reference_wrapper<Source>>)" instead.
-         */
-        static CORRADE_DEPRECATED("use rewind(std::initializer_list<std::reference_wrapper<Source>>) instead") void rewind(std::initializer_list<Source*> sources);
-
         /**
          * @copybrief rewind(const std::vector<std::reference_wrapper<Source>>&)
          * @deprecated Use @ref Magnum::Audio::Source::rewind(const std::vector<std::reference_wrapper<Source>>&) "rewind(const std::vector<std::reference_wrapper<Source>>&)" instead.