acme/autocert: correct typo in comments

Author: aofei

Diff for: acme/autocert/autocert.go

@@ -66,7 +66,7 @@ type HostPolicy func(ctx context.Context, host string) error
 //
 // Note that all hosts will be converted to Punycode via idna.Lookup.ToASCII so that
 // Manager.GetCertificate can handle the Unicode IDN and mixedcase hosts correctly.
-// Invlaid hosts will be silently ignored.
+// Invalid hosts will be silently ignored.
 func HostWhitelist(hosts ...string) HostPolicy {
 	whitelist := make(map[string]bool, len(hosts))
 	for _, h := range hosts {
@@ -252,15 +252,14 @@ func (m *Manager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate,
 	}
 
 	// Note that this conversion is necessary because some server names in the handshakes
-	// made by some clients (like cURL) is not implicitly converted to Punycode, which will
-	// cause the certificate to fail to be obtained. In addition, we should also treat
-	// example.com and EXAMPLE.COM as equivalent and must return the same certificate for
-	// them. Fortunately, this conversion also helped us deal with this kind of mixedcase
-	// problems.
+	// started by some clients (such as cURL) are not converted to Punycode, which will
+	// prevent us from obtaining certificates for them. In addition, we should also treat
+	// example.com and EXAMPLE.COM as equivalent and return the same certificate for them.
+	// Fortunately, this conversion also helped us deal with this kind of mixedcase problems.
 	//
 	// Due to the "σςΣ" problem (see https://unicode.org/faq/idn.html#22), we can't use
 	// idna.Punycode.ToASCII (or just idna.ToASCII) here.
-	name, err := idna.Lookup.ToASCII(hello.ServerName)
+	name, err := idna.Lookup.ToASCII(name)
 	if err != nil {
 		return nil, errors.New("acme/autocert: server name contains invalid character")
 	}