Website: list the machine estimator — menu, sitemap, FAQ and apps-page links; R-997 closed

noindex and the robots Disallow lines removed; both URLs in the sitemap with their hreflang pair; the pair
moves from UNLISTED to TWINS in site_gates.py. The explaining sentence's base figure was already the drawn
box's base; a test now pins it (red-proved).

website/en/sizing.html

@@ -6,7 +6,6 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Which machine do I need? — an estimate for the apps you pick | Felhom.eu</title>
     <meta name="description" content="Tick the apps you would run and see whether they fit an 8, 16 or 32 GB machine. An estimate from measurements on an N100 mini PC.">
-    <meta name="robots" content="noindex">
     <link rel="canonical" href="https://felhom.eu/en/sizing">
     <link rel="alternate" hreflang="hu" href="https://felhom.eu/gepigeny">
     <link rel="alternate" hreflang="en" href="https://felhom.eu/en/sizing">
@@ -39,8 +38,8 @@
         <ul class="nav-links">
                 <li><a href="/en/"><svg class="ico" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-home"/></svg>Home</a></li>
                 <li><a href="/en/services"><svg class="ico" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-rocket"/></svg>Services</a></li>
-                <li class="nav-group">
-                    <button type="button" class="nav-group-toggle" aria-expanded="false" aria-controls="nav-group-apps"><svg class="ico" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-package"/></svg>Applications<svg class="ico nav-chevron" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-chevron-down"/></svg></button>
+                <li class="nav-group is-open">
+                    <button type="button" class="nav-group-toggle active" aria-expanded="true" aria-controls="nav-group-apps"><svg class="ico" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-package"/></svg>Applications<svg class="ico nav-chevron" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-chevron-down"/></svg></button>
                     <ul id="nav-group-apps" class="nav-links nav-links-sub nav-links-nested">
                         <li><a href="/en/apps">About the apps</a></li>
                         <li><a href="/en/apps#files">Files &amp; Office</a></li>
@@ -48,6 +47,7 @@
                         <li><a href="/en/apps#home">Home &amp; Lifestyle</a></li>
                         <li><a href="/en/apps#productivity">Productivity &amp; Knowledge</a></li>
                         <li><a href="/en/apps#system">System &amp; Development</a></li>
+                        <li><a href="/en/sizing" class="active" aria-current="page">Which machine do I need?</a></li>
                     </ul>
                 </li>
                 <li><a href="/en/technology"><svg class="ico" aria-hidden="true"><use href="/assets/icons.svg?v=1#i-layers"/></svg>Technology</a></li>