EXT-2764 EXT-2766 add and remove help ids to reflect reality

indra/newview/skins/default/xui/en/floater_about_land.xml

indra/newview/skins/default/xui/en/floater_preferences.xml

indra/newview/skins/default/xui/en/floater_water.xml

indra/newview/skins/default/xui/en/panel_region_covenant.xml

indra/newview/skins/default/xui/en/panel_region_debug.xml

indra/newview/skins/default/xui/en/panel_region_estate.xml

indra/newview/skins/default/xui/en/panel_region_general.xml

indra/newview/skins/default/xui/en/panel_region_terrain.xml

indra/newview/skins/default/xui/en/panel_region_texture.xml