[book] typos / clarifications in create-instance section
Clarify that cubicweb-ctl upgrade needs to be run whenever cubicweb or a
cube is upgraded. Related to #2632425.
Latest changes --------------* table of `all latest changes`_Links below is providing useful RQL query example..._all latest changes: view?rql=Any+M%2CX+WHERE+X+modification_date+M+ORDERBY+M+DESC+LIMIT+30