fix: redraw the next-alarm widget at midnight

The widget worked out "Today" when it was drawn, and nothing redrew it
when the date changed, so a widget drawn on Monday night still named
Tuesday on Tuesday morning. It now shares the analog faces' midnight
redraw, renamed to MidnightRefresh, and redraws on a clock or zone change.

app/src/main/AndroidManifest.xml

@@ -367,7 +367,7 @@
              updatePeriodMillis is 0 in every provider-info XML — WidgetSync
              is the one refresh trigger for the data widgets, and the analog
              widget's date is redrawn at midnight and on a clock or zone
-             change (widget/AnalogDateRefresh.kt). -->
+             change (widget/MidnightRefresh.kt). -->
         <receiver
             android:name=".widget.NextAlarmWidgetReceiver"
             android:label="@string/widget_next_alarm_label"