Allow reseting notifications

gui/dialogs/SettingsDialog.cpp

@@ -308,6 +308,11 @@ void SettingsDialog::applySettings(SettingsObject *s)
 	s->set("Language",
 		   ui->languageBox->itemData(ui->languageBox->currentIndex()).toLocale().bcp47Name());
 
+	if (ui->resetNotificationsBtn->isChecked())
+	{
+		s->set("ShownNotifications", QString());
+	}
+
 	// Updates
 	s->set("AutoUpdate", ui->autoUpdateCheckBox->isChecked());
 	s->set("UpdateChannel", m_currentUpdateChannel);

gui/dialogs/SettingsDialog.ui

@@ -284,6 +284,16 @@
          </item>
         </layout>
        </item>
+       <item>
+        <widget class="QPushButton" name="resetNotificationsBtn">
+         <property name="text">
+          <string>Reset hidden notifications</string>
+         </property>
+         <property name="checkable">
+          <bool>true</bool>
+         </property>
+        </widget>
+       </item>
        <item>
         <widget class="QGroupBox" name="sortingModeBox">
          <property name="enabled">