Documentation: Update various pages to be in sync with online version

doc/html/en/Contact.html

@@ -46,6 +46,7 @@ our contact form</a>.</div>
 <p>
 We are also present on social media:<br>
 <a title="VeraCrypt on Twitter" href="https://twitter.com/VeraCrypt_IDRIX" target="_blank"><img src="twitter_veracrypt.PNG" alt="VeraCrypt on Twitter" width="168" height="28"></a>&nbsp;&nbsp;
+<a rel="me" title="VeraCrypt on Mastodon" href="https://mastodon.social/@veracrypt" target="_blank"><img src="mastodon_veracrypt.PNG" alt="VeraCrypt on Mastodon" width="69" height="28"></a>&nbsp;&nbsp;
 <a title="VeraCrypt on Facebook" href="https://www.facebook.com/veracrypt" target="_blank"><img src="Home_facebook_veracrypt.png" alt="VeraCrypt on Facebook" width="61" height="28"></a>&nbsp;&nbsp;
 <a title="VeraCrypt on Reddit" href="https://www.reddit.com/r/VeraCrypt/" target="_blank"><img src="Home_reddit.png" alt="VeraCrypt on Reddit" width="94" height="28"></a>
 </p>

doc/html/en/Donation_Bank.html

@@ -74,7 +74,7 @@ Reference: Open Source Donation<br>
 Account Holder: IDRIX SARL<br>
 Account number: 711714051<br>
 BSB Code: 802-985<br>
-Address: Wise, 36-38 Gipps Street, Collingwood VIC 3066, Autralia.<br>
+Address: Wise, 36-38 Gipps Street, Collingwood VIC 3066, Australia.<br>
 Reference: Open Source Donation<br>
 <hr>
 

doc/html/en/Language Packs.html

@@ -47,8 +47,8 @@ To revert to English, select <em style="text-align:left">Settings</em> -&gt; <em
 Language</em>. Then select <em style="text-align:left">English</em> and click <em style="text-align:left">
 OK</em>.</div>
 <div style="text-align:left; margin-top:19px; margin-bottom:19px; padding-top:0px; padding-bottom:0px">
-You can still download an archive containing all language packs for the latest version (1.26.18) from
+You can still download an archive containing all language packs for the latest version (1.26.20) from
-<a href="https://launchpad.net/veracrypt/trunk/1.26.18/+download/VeraCrypt_1.26.18_Language_Files.zip">
+<a href="https://launchpad.net/veracrypt/trunk/1.26.20/+download/VeraCrypt_1.26.20_Language_Files.zip">
 the following link</a>.</div>
 </div>
 </body></html>

doc/html/en/Release Notes.html

@@ -57,7 +57,12 @@
 </li>
 <li><strong>Linux:</strong>
 	<ul>
-	<li>Fix a regression in Linux Mint affecting administrator password authentication (GH #1473).</li>
+	<li>Fix a regression in Linux Mint affecting administrator password authentication (GH #1473).
+	<ul>
+		<li>/usr/bin/true is now used instead of /usr/bin/uptime to detect active sudo sessions.</li>
+		<li>If NOPASSWD used in sudoers with veracrypt and uptime, it should be changed to use /usr/bin/true instead of uptime.</li>
+	</ul>
+	</li>
 	</ul>
 </li>
 <li><strong>macOS:</strong>

doc/html/en/styles.css

@@ -80,3 +80,97 @@
     transform: translateY(-1px);
     transition: all 0.2s ease;
 }
+
+/* Language Selector Styles */
+#lang-selector {
+    position: absolute;
+    top: 18px;
+    right: 32px;
+    z-index: 9999;
+    font-family: inherit;
+    user-select: none;
+  }
+  
+  #lang-selector button {
+    background: #fff;
+    border: 1px solid #08aad7;
+    border-radius: 6px;
+    padding: 6px 12px 6px 8px;
+    display: flex;
+    align-items: center;
+    cursor: pointer;
+    min-width: 110px;
+    font-size: 15px;
+    box-shadow: 0 2px 8px rgba(8,170,215,0.08);
+    transition: border 0.2s;
+  }
+  
+  #lang-selector button:focus {
+    outline: 2px solid #08aad7;
+  }
+  
+  #lang-selector img {
+    width: 20px;
+    height: 13px;
+    border-radius: 3px;
+    margin-right: 7px;
+    vertical-align: middle;
+  }
+  
+  #lang-selector ul {
+    display: none;
+    position: absolute;
+    top: 40px;
+    right: 0;
+    background: #fff;
+    border: 1px solid #08aad7;
+    border-radius: 6px;
+    box-shadow: 0 4px 16px rgba(8,170,215,0.12);
+    margin: 0;
+    padding: 4px 0;
+    min-width: 150px;
+    list-style: none;
+  }
+  
+  #lang-selector ul.open {
+    display: block;
+    animation: fadeIn 0.15s;
+  }
+  
+  @keyframes fadeIn {
+    from { opacity: 0; transform: translateY(-8px);}
+    to { opacity: 1; transform: translateY(0);}
+  }
+  
+  #lang-selector li {
+    display: flex;
+    align-items: center;
+    padding: 7px 16px;
+    cursor: pointer;
+    font-size: 15px;
+    transition: background 0.15s;
+  }
+  
+  #lang-selector li[aria-selected="true"],
+  #lang-selector li:hover,
+  #lang-selector li:focus {
+    background: #e6f7fb;
+  }
+  
+  #lang-selector li img {
+    margin-right: 10px;
+    width: 20px;
+    height: 13px;
+    border-radius: 3px;
+  }
+  
+  @media (max-width: 600px) {
+    #lang-selector {
+      top: 8px;
+      right: 8px;
+      font-size: 14px;
+    }
+    #lang-selector ul {
+      min-width: 110px;
+    }
+  }