docs: add @example JSDoc tag in process/node-version

Adds a missing `@example` tag to `lib/main.js` for `@stdlib/process/node-version`
to align with the rest of the namespace. 11 of 12 sibling packages in
`@stdlib/process` (~92%) carry an `@example` block in `lib/main.js`; node-version
was the only outlier.

https://claude.ai/code/session_01HfYzjX5F2cJnQrKbPhbGNB

Author: claude

lib/node_modules/@stdlib/process/node-version/lib/main.js

@@ -30,6 +30,10 @@ var proc = require( './process.js' );
 *
 * @constant
 * @type {string}
+*
+* @example
+* console.log( VERSION );
+* // => <string>
 */
 var VERSION = proc.versions.node;