Support for keysExamined, docsExamined & hasSortStage across ops/commands

For MongoDB 3.4 docs:

Under SERVER-23257 we added profiler and slow diagnostic log support for keysExamined, docsExamined & hasSortStage across all relevant user read/write commands and operations (see SERVER-23257 for specifics).

Please use this ticket to determine whether DOCS changes are needed and if so to implement them. We currently describe system.profile collection metrics on this page but I do not see that we currently state which operations and commands they apply to.