Fix DC_FORCE_CLEAR_TILE water removal not removing docking tiles

See: https://github.com/OpenTTD/OpenTTD/issues/9869

src/landscape.cpp

@@ -755,7 +755,7 @@ CommandCost CmdLandscapeClear(TileIndex tile, DoCommandFlag flags, uint32 p1, ui
 
 	if (flags & DC_EXEC) {
 		if (c != nullptr) c->clear_limit -= 1 << 16;
-		if (do_clear) DoClearSquare(tile);
+		if (do_clear) ForceClearWaterTile(tile);
 	}
 	return cost;
 }

src/water.h

@@ -44,6 +44,8 @@ static const uint RIVER_OFFSET_DESERT_DISTANCE = 5; ///< Circular tile search ra
 
 bool IsWateredTile(TileIndex tile, Direction from);
 
+void ForceClearWaterTile(TileIndex tile);
+
 /**
  * Calculates the maintenance cost of a number of canal tiles.
  * @param num Number of canal tiles.

src/water_cmd.cpp

@@ -634,6 +634,15 @@ static CommandCost ClearTile_Water(TileIndex tile, DoCommandFlag flags)
 	}
 }
 
+void ForceClearWaterTile(TileIndex tile)
+{
+	bool remove = IsDockingTile(tile);
+	DoClearSquare(tile);
+	MarkCanalsAndRiversAroundDirty(tile);
+	if (remove) RemoveDockingTile(tile);
+	ClearNeighbourNonFloodingStates(tile);
+}
+
 /**
  * return true if a tile is a water tile wrt. a certain direction.
  *