typings: add a few JSDoc typings for the net lib module

PR-URL: https://github.com/nodejs/node/pull/38953
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/net.js

@@ -163,6 +163,16 @@ function isPipeName(s) {
   return typeof s === 'string' && toNumber(s) === false;
 }
 
+/**
+ * Creates a new TCP or IPC server
+ * @param {{
+ *   allowHalfOpen?: boolean;
+ *   pauseOnConnect?: boolean;
+ *   }} [options]
+ * @param {Function} [connectionListener]
+ * @returns {Server}
+ */
+
 function createServer(options, connectionListener) {
   return new Server(options, connectionListener);
 }
@@ -1548,6 +1558,11 @@ function onconnection(err, clientHandle) {
   self.emit('connection', socket);
 }
 
+/**
+ * Gets the number of concurrent connections on the server
+ * @param {Function} cb
+ * @returns {Server}
+ */
 
 Server.prototype.getConnections = function(cb) {
   const self = this;