How many documents can one grant have at most? List the grant id and number.
return grants ;return documents of  #1 ;return number of #2 for each #1 ;return #1 where  #3 is  highest ;return grant id of  #4 ;return documents of  #4 ;return number of #6 ;return #5 ,   #7
['select', 'project', 'group', 'superlative', 'project', 'project', 'aggregate', 'union']