enhance(syntax): 名前空間ブロックのハイライト

Fix #17

aiscript/syntaxes/aiscript.tmLanguage.json

@@ -8,6 +8,9 @@
 		"AiScript"
 	],
 	"patterns": [
+		{
+			"include": "#namespace"
+		},
 		{
 			"include": "#syntax"
 		},
@@ -75,6 +78,22 @@
 				}
 			]
 		},
+		"namespace": {
+			"patterns": [
+				{
+					"name": "meta.namespaceblock.aiscript",
+					"match": "^(:{2})\\s?([a-zA-Z0-9_]+)\\s?\\{",
+					"captures": {
+						"1": {
+							"name": "storage.type.aiscript"
+						},
+						"2": {
+							"name": "entity.name.class.aiscript"
+						}
+					}
+				}
+			]
+		},
 		"functions": {
 			"patterns": [
 				{