all: Modernize error wrapping (#8491)

This replaces old style errors.Wrap with modern fmt.Errorf and removes
the (direct) dependency on github.com/pkg/errors. A couple of cases are
adjusted by hand as previously errors.Wrap(nil, ...) would return nil,
which is not what fmt.Errorf does.

lib/versioner/util.go

@@ -8,14 +8,14 @@ package versioner
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"path/filepath"
 	"regexp"
 	"sort"
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
-
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
@@ -200,11 +200,11 @@ func restoreFile(method fs.CopyRangeMethod, src, dst fs.Filesystem, filePath str
 		case info.IsSymlink():
 			// Remove existing symlinks (as we don't want to archive them)
 			if err := dst.Remove(filePath); err != nil {
-				return errors.Wrap(err, "removing existing symlink")
+				return fmt.Errorf("removing existing symlink: %w", err)
 			}
 		case info.IsRegular():
 			if err := archiveFile(method, dst, src, filePath, tagger); err != nil {
-				return errors.Wrap(err, "archiving existing file")
+				return fmt.Errorf("archiving existing file: %w", err)
 			}
 		default:
 			panic("bug: unknown item type")