Cleanup: remove redundant doxygen \file argument

Move \ingroup onto same line to be more compact and
make it clear the file is in the group.

source/blender/render/intern/source/pipeline.c

@@ -17,8 +17,7 @@
  * All rights reserved.
  */
 
-/** \file blender/render/intern/source/pipeline.c
- *  \ingroup render
+/** \file \ingroup render
  */
 
 #include <math.h>