Fix #4109: Add more water checks to the Oil Rig layout

Prevents Oil Rig docking tile from becoming unreachable by ships when spawning next to each other.

src/table/build_industry.h

@@ -293,6 +293,19 @@ static const IndustryTileTable _tile_table_oil_rig_0[] = {
 	MK(-2, -4, 255),
 	MK(-3, -4, 255),
 	MK(2, 0, 255),
+	MK(2, -1, 255),
+	MK(1, -1, 255),
+	MK(0, -1, 255),
+	MK(-1, -1, 255),
+	MK(-1, 0, 255),
+	MK(-1, 1, 255),
+	MK(-1, 2, 255),
+	MK(-1, 3, 255),
+	MK(0, 3, 255),
+	MK(1, 3, 255),
+	MK(2, 3, 255),
+	MK(2, 2, 255),
+	MK(2, 1, 255),
 	MKEND
 };