labeled the main menu button for screen reader users to help blind people (#1877)

app/js/locales/de-de.json

@@ -407,6 +407,7 @@
     "error_modal_gelocation_na": "App kann deinen aktuellen Standort nicht bestimmen",
     "error_modal_2fa_recent_confirm": "Deine vorherigen Versuche das Konto zurückzusetzen wurden durch den aktiven Nutzer abgebrochen. Bitte in 7 Tagen erneut probieren.",
     "error_modal_2fa_delayed_time_md": "Du kannst dein Konto zurücksetzen in: **{time}**",
+    "head_mainmenu": "Hauptmenü",
     "head_telegram": "Telegram",
     "head_new_group": "Neue Gruppe",
     "head_new_contact": "Neuer Kontakt",
@@ -837,4 +838,4 @@
     "country_select_modal_country_zm": "Sambia",
     "country_select_modal_country_tz_uk": "Sansibar",
     "country_select_modal_country_zw": "Simbabwe"
-}
+}

app/js/locales/en-us.json

@@ -460,7 +460,7 @@
 	"error_modal_2fa_recent_confirm": "Your recent attempts to reset this account have been cancelled by its active user. Please try again in 7 days.",
 	"error_modal_2fa_delayed_time_md": "You'll be able to reset your account in: **{time}**",
 
-
+	"head_mainmenu": "Main menu",
 	"head_telegram": "Telegram",
 	"head_new_group": "New group",
 	"head_new_contact": "New contact",

app/less/app.less

@@ -5023,4 +5023,10 @@ a.countries_modal_search_clear {
   }
 }
 
-
+.visually-hidden { /* https://snook.ca/archives/html_and_css/hiding-content-for-accessibility */
+  position: absolute !important;
+  height: 1px; width: 1px;
+  overflow: hidden;
+  clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
+  clip: rect(1px, 1px, 1px, 1px);
+}

app/partials/desktop/head.html

@@ -4,6 +4,7 @@
     <div class="tg_head_logo_wrap">
       <div class="tg_head_logo_dropdown dropdown" dropdown>
         <a class="tg_head_btn dropdown-toggle" dropdown-toggle>
+          <span class="visually-hidden" my-i18n="head_mainmenu"></span>
           <div class="icon-hamburger-wrap">
             <span class="icon-bar"></span>
             <span class="icon-bar"></span>
@@ -112,4 +113,4 @@
       </div>
     </div>
   </div>
-</div>
+</div>