feat: js/py generate declarations from comments (#30)

tools/demo_tool.js

@@ -0,0 +1,16 @@
+/**
+ * Demonstrate how to create a tool using Javascript and how to use comments.
+ * @typedef {Object} Args
+ * @property {string} string - Define a required string property
+ * @property {'foo'|'bar'} string_enum - Define a required string property with enum
+ * @property {string} [string_optional] - Define a optional string property
+ * @property {boolean} boolean - Define a required boolean property
+ * @property {Integer} integer - Define a required integer property
+ * @property {number} number - Define a required number property
+ * @property {string[]} array - Define a required string array property
+ * @property {string[]} [array_optional] - Define a optional string array property
+ * @param {Args} args
+ */
+exports.main = function main(args) {
+  console.log(args);
+}