[docs] Note that no http settings are dynamic

Closes #13364

docs/reference/modules/http.asciidoc

@@ -91,6 +91,8 @@ simple message will be returned. Defaults to `true`
 It also uses the common
 <<modules-network,network settings>>.
 
+Note that none of these settings is dynamically updatable.
+
 [float]
 === Disable HTTP