Docs for SERVER-39147: Always baton

Description

Description:

This removes the AsyncRequestsSenderUseBaton setParameter. This parameter toggled a performance enhancement introduced in 4.0 which is now always on

Engineering Ticket Description:

Change the baton so that we bind one on opCtx creation and detach on destruction (so that we always have a baton

Scope of changes

• Remove AsyncRequestsSenderUseBaton from the documentation

Impact to Other Docs

MVP (Work and Date)

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