doxygen: add newline after \file

While \file doesn't need an argument, it can't have another doxy
command after it.

source/blender/python/generic/blf_py_api.h

@@ -17,7 +17,8 @@
 #ifndef __BLF_PY_API_H__
 #define __BLF_PY_API_H__
 
-/** \file \ingroup pygen
+/** \file
+ * \ingroup pygen
  */
 
 PyObject *BPyInit_blf(void);