edit variable definition

sample/vars/declare-core.json

@@ -0,0 +1,23 @@
+{
+  "name": "def-core",
+  "desc": "",
+  "firstid": 1,
+  "export": true,
+  "declare": {
+    "imports": [],
+    "vars": [
+      {
+        "name": "context",
+        "desc": "上下文"
+      },
+      {
+        "name": "version",
+        "desc": "版本"
+      }
+    ]
+  },
+  "root": {
+    "id": 1,
+    "name": "Sequence"
+  }
+}