user_nl_datm comment gives incorrect advice

[samsrabin]

In user_nl_datm, a comment says:

! To modify the contents of a stream txt file, first use preview_namelists
! to obtain the contents of the stream txt files in CaseDocs, and then
! place a copy of the  modified stream txt file in $CASEROOT with the string
! user_ prepended.

This seems to be outdated, per conversation just now with @ekluzek. Instead, this should point to user_nl_datm_streams.

(Using cdeps1.0.13.)