Fix staticcheck warnings

$ staticcheck ./... | fmt -w 80 -s
internal/format/format.go:204:17: error strings should not end with punctuation
or newlines (ST1005)
internal/stream/stream.go:15:2: "golang.org/x/crypto/poly1305" is
deprecated: Poly1305 as implemented by this package is a cryptographic
building block that is not safe for general purpose use. For
encryption, use the full ChaCha20-Poly1305 construction implemented by
golang.org/x/crypto/chacha20poly1305. For authentication, use a general
purpose MAC such as HMAC implemented by crypto/hmac.  (SA1019)
plugin/client.go:385:2: field stderr is unused (U1000)

$ gotip vet ./cmd/...
cmd/age-keygen/keygen.go:161:13: non-constant format string in call to log.Printf

cmd/age-keygen/keygen.go

@@ -158,5 +158,5 @@ func errorf(format string, v ...interface{}) {
 }
 
 func warning(msg string) {
-	log.Printf("age-keygen: warning: " + msg)
+	log.Printf("age-keygen: warning: %s", msg)
 }

internal/format/format.go

@@ -201,7 +201,7 @@ func (r *StanzaReader) ReadStanza() (s *Stanza, err error) {
 		b, err := DecodeString(strings.TrimSuffix(string(line), "\n"))
 		if err != nil {
 			if bytes.HasPrefix(line, footerPrefix) || bytes.HasPrefix(line, stanzaPrefix) {
-				return nil, fmt.Errorf("malformed body line %q: stanza ended without a short line\nNote: this might be a file encrypted with an old beta version of age or rage. Use age v1.0.0-beta6 or rage to decrypt it.", line)
+				return nil, fmt.Errorf("malformed body line %q: stanza ended without a short line\nNote: this might be a file encrypted with an old beta version of age or rage. Use age v1.0.0-beta6 or rage to decrypt it", line)
 			}
 			return nil, errorf("malformed body line %q: %v", line, err)
 		}

internal/stream/stream.go

@@ -12,7 +12,6 @@ import (
 	"io"
 
 	"golang.org/x/crypto/chacha20poly1305"
-	"golang.org/x/crypto/poly1305"
 )
 
 const ChunkSize = 64 * 1024
@@ -29,7 +28,7 @@ type Reader struct {
 }
 
 const (
-	encChunkSize  = ChunkSize + poly1305.TagSize
+	encChunkSize  = ChunkSize + chacha20poly1305.Overhead
 	lastChunkFlag = 0x01
 )
 

plugin/client.go

@@ -9,7 +9,6 @@ package plugin
 
 import (
 	"bufio"
-	"bytes"
 	"fmt"
 	"io"
 	"math/rand"
@@ -382,7 +381,6 @@ type clientConnection struct {
 	cmd       *exec.Cmd
 	io.Reader // stdout
 	io.Writer // stdin
-	stderr    bytes.Buffer
 	close     func()
 }