Allow to create invoices before bank transfer runs (#1734)

Co-authored-by: Raphael Michel <michel@rami.io>

src/pretix/presale/checkoutflow.py

@@ -141,7 +141,7 @@ def get_checkout_flow(event):
     # Sort by priority
     flow.sort(key=lambda p: p.priority)
 
-    # Create a double-linked-list for esasy forwards/backwards traversal
+    # Create a double-linked-list for easy forwards/backwards traversal
     last = None
     for step in flow:
         step._previous = last