PyAPI: expose bpy.types.bpy_prop_collection_idprop

Expose the IDProperty sub-class of `bpy.types.bpy_prop_collection`,
needed for API doc generation but should have been exposed for
completeness.

source/blender/python/intern/bpy_rna.cc

@@ -8642,6 +8642,7 @@ PyObject *BPY_rna_types()
         &pyrna_prop_Type,
         &pyrna_prop_array_Type,
         &pyrna_prop_collection_Type,
+        &pyrna_prop_collection_idprop_Type,
         &pyrna_func_Type,
     };