docs: Add comment explain why matcher is removed

rust/pact_ffi/src/mock_server/form_urlencoded.rs

@@ -144,7 +144,7 @@ mod test {
     "number_value_with_matcher_and_generator=123".to_string(),
     matchingrules_list!{"body"; "$.number_value_with_matcher_and_generator" => [MatchingRule::Number]}
   )]
-  // Missing value => null + generators will be used => but they are not supported, so it's fine to remove the matcher.
+  // Missing value => null will be used => but it is not supported, so matcher is removed.
   #[case(
     json!({ "number_matcher_only": { "pact:matcher:type": "number", "min": 0, "max": 10 } }),
     "".to_string(),