hdf5doc

I made two changes to the H5Oget_info RM entry to clarify what seems 
to have been unclear to the reporting user. The first change is I added 
the following comment after the H5O_type_t structure: Note that object_id 
refers only to the types specified by H5O_type_t. The second change is in 
the description of the object_id parameter in the Parameters section. 
The old description was "IN: Identifier for target object". The new 
description is "IN: Identifier for object of type specified by 
H5O_type_t". See HDFFV-8913

Tested: Firefox