Revert "Fixes spelling and grammar in manuals"

This reverts commit b8f1c7937dc9916ebb0dac8033c2ee8595447f8b.

Manual are generated automatically. Changes should be made to the
header files of the R scripts themselves.
Fixes spelling and grammar in script headers

Minor edits to headers in:
    * R/ds.glm.R
    * R/glmhelper2.R

Signed-off-by: Andrew Turner <andrewjamesturner0@gmail.com>