add tab description and download dialog bag button

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -359,6 +359,7 @@ public class DownloadDialog extends DialogFragment implements RadioGroup.OnCheck
         toolbar.setNavigationIcon(isLight ? R.drawable.ic_arrow_back_black_24dp : R.drawable.ic_arrow_back_white_24dp);
         toolbar.inflateMenu(R.menu.dialog_url);
         toolbar.setNavigationOnClickListener(v -> getDialog().dismiss());
+        toolbar.setNavigationContentDescription(R.string.cancel);
 
         okButton = toolbar.findViewById(R.id.okay);
         okButton.setEnabled(false);// disable until the download service connection is done

app/src/main/java/org/schabi/newpipe/fragments/MainFragment.java

@@ -159,6 +159,7 @@ public class MainFragment extends BaseFragment implements TabLayout.OnTabSelecte
 
         viewPager.setOffscreenPageLimit(pagerAdapter.getCount());
         updateTabsIcon();
+        updateTabsContentDescription();
         updateCurrentTitle();
     }
 
@@ -171,6 +172,17 @@ public class MainFragment extends BaseFragment implements TabLayout.OnTabSelecte
         }
     }
 
+    private void updateTabsContentDescription() {
+        for (int i = 0; i < tabsList.size(); i++) {
+            final TabLayout.Tab tabToSet = tabLayout.getTabAt(i);
+            if (tabToSet != null) {
+                final Tab t = tabsList.get(i);
+                tabToSet.setIcon(t.getTabIconRes(activity));
+                tabToSet.setContentDescription(t.getTabName(activity));
+            }
+        }
+    }
+
     private void updateCurrentTitle() {
         setTitle(tabsList.get(viewPager.getCurrentItem()).getTabName(requireContext()));
     }