SceneTools: remove the forward-declaration header.

There's nothing to forward-declare and probably never will be, same as
with MeshTools for example. So this is just bloat.

modules/FindMagnum.cmake

@@ -901,6 +901,10 @@ foreach(_component ${Magnum_FIND_COMPONENTS})
 
         # No special setup for SceneGraph library
 
+        # SceneTools library
+        elseif(_component STREQUAL SceneTools)
+            set(_MAGNUM_${_COMPONENT}_INCLUDE_PATH_NAMES FlattenMeshHierarchy.h)
+
         # ShaderTools library
         elseif(_component STREQUAL ShaderTools)
             set_property(TARGET Magnum::${_component} APPEND PROPERTY

src/Magnum/SceneTools/CMakeLists.txt

@@ -49,7 +49,6 @@ set(MagnumSceneTools_GracefulAssert_SRCS
 set(MagnumSceneTools_HEADERS
     FlattenMeshHierarchy.h
     OrderClusterParents.h
-    SceneTools.h
 
     visibility.h)
 

src/Magnum/SceneTools/SceneTools.h

@@ -1,42 +0,0 @@
-#ifndef Magnum_SceneTools_SceneTools_h
-#define Magnum_SceneTools_SceneTools_h
-/*
-    This file is part of Magnum.
-
-    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
-                2020, 2021, 2022 Vladimír Vondruš <mosra@centrum.cz>
-
-    Permission is hereby granted, free of charge, to any person obtaining a
-    copy of this software and associated documentation files (the "Software"),
-    to deal in the Software without restriction, including without limitation
-    the rights to use, copy, modify, merge, publish, distribute, sublicense,
-    and/or sell copies of the Software, and to permit persons to whom the
-    Software is furnished to do so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included
-    in all copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
-    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-    DEALINGS IN THE SOFTWARE.
-*/
-
-/** @file
- * @brief Forward declarations for the @ref Magnum::SceneTools namespace
- * @m_since_latest
- */
-
-#include "Magnum/configure.h"
-
-namespace Magnum { namespace SceneTools {
-
-#ifndef DOXYGEN_GENERATING_OUTPUT
-#endif
-
-}}
-
-#endif