docs: update pmseries(1) for query expressions and functions
docs: update pmseries(1) for query expressions and functions

Resolves: https://github.com/performancecopilot/pcp/issues/1097
Resolves: https://github.com/performancecopilot/pcp/issues/1098

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp