[freeciv-data] (PR#2406) In help, Rivers are indexed under mountains

[rfalke - Tue Nov 26 11:18:59 2002]:

> I think this is the wrong approach. All three (rivers, terrain
> alterations and pillaging) are special. And all three should be 
> indented by another column. The attached patch fixes this.
> 
> The alternative would be to rename "Terrain" into "Terrain types" and 
> add these three under a new item "Terrain".
> 
>     Raimar

Now I see that this problem only bothers GTK 2. These twice-indented
items are hidden until the last item (in Finnish, mountains - in English evidently
tundra, but I didn't chck) is expanded. Otherwise the expansion mechanism
is OK, although I'd suggest that when I choose a topic from Help menu, it
would be expanded automagically.

So I think that the second alternative is better.