doc: 'constructor' implies use of new keyword

The square module is described as exporting a constructor,
which would mean it would need to be invoked with the
new keyword in bar.js after requiring it. Otherwise it's
technically a factory function, not a constructor.

PR-URL: #17364
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>

Author: CameronMoorehead

doc/api/modules.md

@@ -41,9 +41,9 @@ or object).
 Below, `bar.js` makes use of the `square` module, which exports a constructor:
 
 ```js
-const square = require('./square.js');
-const mySquare = square(2);
-console.log(`The area of my square is ${mySquare.area()}`);
+const Square = require('./square.js');
+const mySquare = new Square(2);
+console.log(`The area of mySquare is ${mySquare.area()}`);
 ```
 
 The `square` module is defined in `square.js`: