Adds the untimed std::shared_mutex. Editor kept 'Shared timed mutex types' nested under 'Mutex requirements' rather than under 'Shared mutex types', for consistency with sibling subclauses..
Adds the untimed std::shared_mutex. Editor kept 'Shared timed mutex types' nested under 'Mutex requirements' rather than under 'Shared mutex types', for consistency with sibling subclauses..