Room & member filter fields: support (shift+)tab

TODO.md

@@ -2,7 +2,6 @@
 
 - server list sorting method / explain what the % number is (stability)
 - server list: make it more obvious that it can be scrolled
-- support (shift+)tab in filter fields
 - clicking cancel on SSO "waiting" box doesn't do anything the first time
 - spam alt+shift+a when starting app on server browser → segfault
 - remove items.Device

src/gui/MainPane/BottomBar.qml

@@ -51,6 +51,8 @@ Rectangle {
             Keys.forwardTo: [roomList]
             Keys.priority: Keys.AfterItem
 
+            Keys.onTabPressed: roomList.incrementCurrentIndex()
+            Keys.onBacktabPressed: roomList.decrementCurrentIndex()
             Keys.onEnterPressed: Keys.onReturnPressed(event)
             Keys.onReturnPressed: {
                 roomList.showItemAtIndex()

src/gui/Pages/Chat/RoomPane/MemberView/MemberView.qml

@@ -48,6 +48,9 @@ HColumnLayout {
                 )
             }
 
+            Keys.onTabPressed: memberList.incrementCurrentIndex()
+            Keys.onBacktabPressed: memberList.decrementCurrentIndex()
+
             Keys.onEnterPressed: Keys.onReturnPressed(event)
             Keys.onReturnPressed: {
                 currentItem.leftClicked()