Docs for SERVER-39267: Guard opWriteConcernCounters behind flag

Description

Description:

The opWriteConcernCounters section of serverStatus will only be included if the node is started with the setParameter reportOpWriteConcernCountersInServerStatus=true.

Engineering Ticket Description:

The opWriteConcernCounters section of serverStatus should be disabled by default, with a flag to enable it, since it can have negative performance impact when SSL is disabled. (When SSL is enabled, other mutexes dominate.)

Scope of changes

since 4.0.6 (and whenever we know 3.6.x)
just:

• source/reference/command/serverStatus.txt
• source/includes/extracts-server-status-projection-base.yaml
• parameters

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)