Show ellipses for leaving rooms and space actions, and always confirm

The HIG suggests using ellipses for actions that have a confirmation,
and leaving a space or room is one such cases. Otherwise, the user has
no idea if leaving is an immediate, irreversible action.

It turns out there *was* some cases where pressing this button
(especially for spaces) would actually do it without confirmation, which
is now fixed.

src/roominfo/RoomInformation.qml

@@ -153,7 +153,7 @@ QQC2.ScrollView {
             Delegates.RoundedItemDelegate {
                 id: leaveButton
                 icon.name: "arrow-left-symbolic"
-                text: root.room.isSpace ? i18nc("@action:button", "Leave this space") : i18nc("@action:button", "Leave this room")
+                text: root.room.isSpace ? i18nc("@action:button", "Leave this space…") : i18nc("@action:button", "Leave this room…")
                 activeFocusOnTab: true
 
                 Layout.fillWidth: true