Use separate tool-tip string for building rivers in game

See: #378

src/dock_gui.cpp

@@ -336,7 +336,7 @@ static const NWidgetPart _nested_build_docks_toolbar_widgets[] = {
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_DEPOT), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_SHIP_DEPOT, STR_WATERWAYS_TOOLBAR_BUILD_DEPOT_TOOLTIP),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_STATION), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_SHIP_DOCK, STR_WATERWAYS_TOOLBAR_BUILD_DOCK_TOOLTIP),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_BUOY), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUOY, STR_WATERWAYS_TOOLBAR_BUOY_TOOLTIP),
-		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_RIVER), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUILD_RIVER, STR_WATERWAYS_TOOLBAR_CREATE_RIVER_TOOLTIP),
+		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_RIVER), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUILD_RIVER, STR_WATERWAYS_TOOLBAR_CREATE_RIVER_IN_GAME_TOOLTIP),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_BUILD_AQUEDUCT), SetMinimalSize(23, 22), SetFill(0, 1), SetDataTip(SPR_IMG_AQUEDUCT, STR_WATERWAYS_TOOLBAR_BUILD_AQUEDUCT_TOOLTIP),
 	EndContainer(),
 };

src/lang/english.txt

@@ -3614,6 +3614,7 @@ STR_WATERWAYS_TOOLBAR_BUOY_TOOLTIP                              :{BLACK}Place a
 STR_WATERWAYS_TOOLBAR_BUILD_AQUEDUCT_TOOLTIP                    :{BLACK}Build aqueduct. Shift toggles building/showing cost estimate
 STR_WATERWAYS_TOOLBAR_CREATE_LAKE_TOOLTIP                       :{BLACK}Define water area.{}Make a canal, unless Ctrl is held down at sea level, when it will flood the surroundings instead
 STR_WATERWAYS_TOOLBAR_CREATE_RIVER_TOOLTIP                      :{BLACK}Place rivers. Ctrl selects the area diagonally
+STR_WATERWAYS_TOOLBAR_CREATE_RIVER_IN_GAME_TOOLTIP              :{BLACK}Place rivers
 
 # Ship depot construction window
 STR_DEPOT_BUILD_SHIP_CAPTION                                    :{WHITE}Ship Depot Orientation