resource: add short_grass block type

Besides adding a number of experimental block types for the 1.21 preview,
Minecraft 1.20.3 also renamed the "grass" block to "short grass"
internally. Add the new block name to avoid warnings during generation.

crates/resource/src/block_types.rs

@@ -5694,6 +5694,13 @@ pub const BLOCK_TYPES: &[(&str, BlockType)] = &[
 			color: Color([0, 0, 0]),
 		},
 	),
+	(
+		"short_grass",
+		BlockType {
+			flags: make_bitflags!(BlockFlag::{}),
+			color: Color([0, 0, 0]),
+		},
+	),
 	(
 		"shroomlight",
 		BlockType {

resource/blocks.json

@@ -1558,6 +1558,7 @@
 	"sea_lantern": {},
 	"sea_pickle": {},
 	"seagrass": null,
+	"short_grass": null,
 	"shroomlight": {},
 	"shulker_box": {},
 	"sign": {