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/python/intern/bpy_intern_string.c

@@ -14,8 +14,7 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
-/** \file blender/python/intern/bpy_intern_string.c
- *  \ingroup pythonintern
+/** \file \ingroup pythonintern
  *
  * Store python versions of strings frequently used for python lookups
  * to avoid converting, creating the hash and freeing every time as