update format call to inline path

Co-authored-by: David Herberth <github@dav1d.de>
Signed-off-by: Greg Cusack <greg.cusack@solana.com>

examples/dynamic_jsonpath.rs

@@ -17,7 +17,7 @@ async fn main() -> anyhow::Result<()> {
     let field_selector = std::env::var("FIELD_SELECTOR").unwrap_or_default();
     let jsonpath = {
         let path = std::env::var("JSONPATH").unwrap_or_else(|_| ".items[*].spec.containers[*].image".into());
-        format!("{}{}", "$", path.clone())
+        format!("${path}")
             .parse::<JsonPathInst>()
             .map_err(Error::msg)
             .with_context(|| {