Resolve uninlined_format_args pedantic clippy lint in test suite

    error: variables can be used directly in the `format!` string
        --> test_suite/tests/test_annotations.rs:1238:30
         |
    1238 |     serializer.serialize_str(format!("{};{:?}", f1, f2).as_str())
         |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args
         = note: `-D clippy::uninlined-format-args` implied by `-D clippy::pedantic`
    help: change this to
         |
    1238 -     serializer.serialize_str(format!("{};{:?}", f1, f2).as_str())
    1238 +     serializer.serialize_str(format!("{f1};{f2:?}").as_str())
         |

test_suite/tests/test_annotations.rs

@@ -1235,7 +1235,7 @@ fn serialize_variant_as_string<S>(f1: &str, f2: &u8, serializer: S) -> Result<S:
 where
     S: Serializer,
 {
-    serializer.serialize_str(format!("{};{:?}", f1, f2).as_str())
+    serializer.serialize_str(format!("{f1};{f2:?}").as_str())
 }
 
 fn deserialize_string_as_variant<'de, D>(deserializer: D) -> Result<(String, u8), D::Error>