doc: fix http2 sample code for http2.md

PR-URL: #14667
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

doc/api/http2.md

@@ -1242,7 +1242,7 @@ const {
   HTTP2_HEADER_CONTENT_TYPE
 } = http2.constants;
 
-const server = http.createServer();
+const server = http2.createServer();
 server.on('stream', (stream, headers, flags) => {
   const method = headers[HTTP2_HEADER_METHOD];
   const path = headers[HTTP2_HEADER_PATH];
@@ -1328,7 +1328,7 @@ const {
 
 const options = getOptionsSomehow();
 
-const server = http.createSecureServer(options);
+const server = http2.createSecureServer(options);
 server.on('stream', (stream, headers, flags) => {
   const method = headers[HTTP2_HEADER_METHOD];
   const path = headers[HTTP2_HEADER_PATH];
@@ -2373,7 +2373,7 @@ to [`response.writeHead()`][] given precedence.
 
 ```js
 // returns content-type = text/plain
-const server = http.createServer((req, res) => {
+const server = http2.createServer((req, res) => {
   res.setHeader('Content-Type', 'text/html');
   res.setHeader('X-Foo', 'bar');
   res.writeHead(200, { 'Content-Type': 'text/plain' });
@@ -2416,8 +2416,8 @@ via `response.connection`.
 Example:
 
 ```js
-const http = require('http');
-const server = http.createServer((req, res) => {
+const http2 = require('http2');
+const server = http2.createServer((req, res) => {
   const ip = req.socket.remoteAddress;
   const port = req.socket.remotePort;
   res.end(`Your IP address is ${ip} and your source port is ${port}.`);