refactor: rewrite cert::fingerprint once again

examples/simple.rs

@@ -1,8 +1,5 @@
 use tokio_gemini::{
-    certs::{
-        fingerprint::{self, CertFingerprint},
-        SelfsignedCertVerifier,
-    },
+    certs::{fingerprint::CertFingerprint, SelfsignedCertVerifier},
     Client, LibError,
 };
 
@@ -47,7 +44,7 @@ impl SelfsignedCertVerifier for CertVerifier {
         eprintln!(
             "Host = {}\nFingerprint = {}",
             host,
-            CertFingerprint::<fingerprint::Sha256>::new(cert).base64(),
+            CertFingerprint::new_sha256(cert).base64(),
         );
         Ok(true)
     }