include node_modules so release .zip is deployable

node_modules/ext/docs/promise/limit.md

@@ -0,0 +1,13 @@
+# `Promise.limit` _(ext/promise/limit)_
+
+Helps to limit concurrency of asynchronous operations.
+
+```javascript
+const limit = require("ext/promise/limit").bind(Promise);
+
+const limittedAsyncFunction = limit(2, asyncFunction);
+
+imittedAsyncFunction(); // Async operation started
+imittedAsyncFunction(); // Async operation started
+imittedAsyncFunction(); // On hold until one of previously started finalizes
+```