doc: add option to require 'process' to api docs

It is possible to require the 'process' module and with the upcoming
support for ES Modules, importing 'process' might be the more favorable
way for developers. This commit adds that option to the documentation.

PR-URL: #26792
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: dkundel

doc/api/process.md

@@ -5,7 +5,12 @@
 
 The `process` object is a `global` that provides information about, and control
 over, the current Node.js process. As a global, it is always available to
-Node.js applications without using `require()`.
+Node.js applications without using `require()`. It can also be explicitly
+accessed using `require()`:
+
+```js
+const process = require('process');
+```
 
 ## Process Events