Third arg DOC is the group documentation.
MEMBERS should be an alist of the form ((NAME WIDGET)...) where
-NAME is a symbol and WIDGET is a widget is a widget for editing that
-symbol. Useful widgets are `custom-variable' for editing variables,
+NAME is a symbol and WIDGET is a widget for editing that symbol.
+Useful widgets are `custom-variable' for editing variables,
`custom-face' for edit faces, and `custom-group' for editing groups.
The remaining arguments should have the form