add comment on endpoint functions nesting

Author: mcucchi9

ogc_api_processes_fastapi/endpoints.py

@@ -147,6 +147,11 @@ def get_conformance(request: fastapi.Request) -> models.ConfClass:
     return get_conformance
 
 
+# The nesting of endpoint functions inside generator functions is needed
+# to be able to pass the client to the endpoint function.
+# Client is passed as a dependency to the endpoint function so that all its
+# arguments are resolved as endpoints parameters and correctly inserted in the
+# automatic documentation.
 def create_get_processes_endpoint(
     client: clients.BaseClient,
 ) -> Callable[[fastapi.Request], models.ProcessList]: