Adjust margin on arrow when group leader is open
Adjust margin on arrow when group leader is open

The "fa-caret-down" icon is a little wider than "fa-caret-right". I
lowered the margin-right value so the parameter description text
wouldn't jump when toggling the visibility of the group items.

csdms/wmt-client,mdpiper/wmt-client,csdms/wmt-client,mdpiper/wmt-client,csdms/wmt-client,mdpiper/wmt-client