clarify/correct man page for GForce (#2412)
clarify/correct man page for GForce (#2412)

Related to #2411, noticed some bad grammar/need for elucidation.
Rdatatable/data.table,vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,Rdatatable/data.table,vlulla/data.table,vlulla/data.table,jangorecki/data.table,jangorecki/data.table