Cleanup: ensure space after file named in headers

Add blank lines after file references to avoid them being interpreted as
doc-strings the following declarations.

source/blender/python/BPY_extern_clog.h

@@ -9,5 +9,6 @@
 #pragma once
 
 /* bpy_interface.c */
+
 extern struct CLG_LogRef *BPY_LOG_RNA;
 extern struct CLG_LogRef *BPY_LOG_CONTEXT;