fix spelling

server/certificates/certificates.go

@@ -408,7 +408,7 @@ func MaintainCertDB(ctx context.Context, interval time.Duration, acmeClient *Acm
 
 // leaf returns the parsed leaf certificate, either from c.Leaf or by parsing
 // the corresponding c.Certificate[0].
-// After successfuly parsing the cert c.Leaf gets set to the parsed cert.
+// After successfully parsing the cert c.Leaf gets set to the parsed cert.
 func leaf(c *tls.Certificate) (*x509.Certificate, error) {
 	if c.Leaf != nil {
 		return c.Leaf, nil