Improve menu how-to in index, add to FAQ menus

The index.html file (from index.md) now links to the no JavaScript menu
for those who either wish to use a plaintext menu or for those who the
menu does not work (like I discovered with my iPhone 8 Plus - iOS 16
Safari, a bug that was fixed in iOS 17). It also links to a new FAQ
about the menus: how they work and also what to do if they don't work.
By 'how they work' this refers to on desktop/laptops, on mobile devices:
without JavaScript enabled and also on mobile phones and tablets in
portrait and also landscape mode plus on mobile devices wider than 1024
pixels and also the browser bug I referred to above.

This includes three new png files, screenshots of how it looks on an
iPhone 14 Pro Max (which should be like other mobile phones), one which
shows the iOS 16 Safari bug and one which shows desktops. These are of
course used in the FAQ.

Although not every html file has a link to the plaintext (i.e. the menu
for those with JavaScript disabled), it is hoped that these two changes
will help people navigate if they have a problem with the menus.

index.html

@@ -405,7 +405,9 @@ then consider making pull requests against the <a href="https://github.com/ioccc
       width=24 height=24></a> in the upper right corner, click on it to display the menu.</p>
 <p>On a <strong>touchscreen mobile device</strong> browser <strong>wider than 1024 pixels</strong>,
 <strong>press and hold</strong> the menu you wish to activate (in the upper right corner) in
-order to activate the pull-down.</p>
+order to activate the pull-down. If this does not work or you prefer to use a
+plaintext menu even with JavaScript enabled, you can do so
+<a href="nojs-menu.html">here</a>. See also the <a href="faq.html#menus">FAQ on menus</a>.</p>
 <h1 id="obfuscate-defined">Obfuscate defined:</h1>
 <p>tr.v. -cated, -cating, -cates.
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