Fix the spelling mistake

opentech/apply/funds/blocks.py

@@ -109,7 +109,7 @@ class MustIncludeStatic(StaticBlock):
         super().__init__(*args, **kwargs)
 
     class Meta:
-        admin_text = 'Much be included in the form only once.'
+        admin_text = 'Must be included in the form only once.'
 
     def render_form(self, *args, **kwargs):
         errors = kwargs.pop('errors')