add an intuitive prefix for the duration of lists on UI, and avoid using the new prefix for single videos

Author: bg1722

app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java

@@ -506,7 +506,7 @@ private void setStreamCountAndOverallDuration(final List<StreamInfoItem> list,
                 Localization.concatenateStrings(
                     Localization.localizeStreamCount(activity, streamCount),
                     Localization.getDurationString(playlistOverallDurationSeconds,
-                            isDurationComplete))
+                            isDurationComplete, true))
             );
         }
     }

app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java

@@ -837,7 +837,8 @@ private void setStreamCountAndOverallDuration(final ArrayList<LocalItem> itemsLi
             headerBinding.playlistStreamCount.setText(
                     Localization.concatenateStrings(
                             Localization.localizeStreamCount(activity, streamCount),
-                            Localization.getDurationString(playlistOverallDurationSeconds))
+                            Localization.getDurationString(playlistOverallDurationSeconds,
+                                                            true, true))
             );
         }
     }

app/src/main/java/org/schabi/newpipe/util/Localization.java

@@ -245,7 +245,7 @@ public static String likeCount(@NonNull final Context context, final int likeCou
      * @return a formatted duration String or {@code 0:00} if the duration is zero.
      */
     public static String getDurationString(final long duration) {
-        return getDurationString(duration, true);
+        return getDurationString(duration, true, false);
     }
 
     /**
@@ -254,9 +254,11 @@ public static String getDurationString(final long duration) {
      * duration string.
      * @param duration the duration in seconds
      * @param isDurationComplete whether the given duration is complete or whether info is missing
+     * @param showDurationPrefix whether the duration-prefix shall be shown
      * @return a formatted duration String or {@code 0:00} if the duration is zero.
      */
-    public static String getDurationString(final long duration, final boolean isDurationComplete) {
+    public static String getDurationString(final long duration, final boolean isDurationComplete,
+                                           final boolean showDurationPrefix) {
         final String output;
 
         final long days = duration / (24 * 60 * 60L); /* greater than a day */
@@ -274,8 +276,9 @@ public static String getDurationString(final long duration, final boolean isDura
         } else {
             output = String.format(Locale.US, "%d:%02d", minutes, seconds);
         }
+        final String durationPrefix = showDurationPrefix ? "⏱ " : "";
         final String durationPostfix = isDurationComplete ? "" : "+";
-        return output + durationPostfix;
+        return durationPrefix + output + durationPostfix;
     }
 
     /**