feat: update wording of booking button to better match actual function

templates/groups/booking/step_4.html.twig

@@ -138,7 +138,7 @@
                         hx-get="{{ path('app_groups_booking_step_4_confirm') }}"
                         hx-target="body"
                         hx-swap="beforeend">
-                    Jetzt verbindlich buchen
+                    Buchung abschließen
                 </button>
             </div>
         </div>

templates/groups/offer/view.html.twig

@@ -81,7 +81,7 @@
                             hx-get="{{ path('app_groups_offer_confirm', { uuid: booking.uuid }) }}"
                             hx-target="body"
                             hx-swap="beforeend">
-                        Angebot verbindlich buchen
+                        Angebot buchen
                     </button>
                 </div>
             {% elseif booking.confirmedAt is not null %}