style: very tiny nitpicking

program/filters.py

@@ -302,7 +302,7 @@ class VirtualTimeslotFilterSet(filters.FilterSet):
     end = filters.IsoDateTimeFilter(method="filter_noop")
     cut_at_range_boundaries = filters.BooleanFilter(
         help_text=(
-            "If true guarantees that the first and last program entry match the requested range"
+            "If true guarantees that the first and last program entry match the requested range "
             "even if these entries earlier or end later."
         ),
         method="filter_noop",