all: apply modernisers

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/pkg.go

@@ -238,8 +238,8 @@ func (t *TContext) destroy(errP *error) {
 		if chmodErr != nil || removeErr != nil {
 			*errP = errors.Join(*errP, chmodErr, removeErr)
 		} else if errors.Is(*errP, os.ErrExist) {
-			var linkError *os.LinkError
-			if errors.As(*errP, &linkError) && linkError != nil &&
+			if linkError, ok := errors.AsType[*os.LinkError](*errP); ok &&
+				linkError != nil &&
 				linkError.Op == "rename" {
 				// two artifacts may be backed by the same file
 				*errP = nil
@@ -974,36 +974,42 @@ func (e *ScrubError) Unwrap() []error {
 // Error returns a multi-line representation of [ScrubError].
 func (e *ScrubError) Error() string {
 	var segments []string
+	var buf strings.Builder
+
 	if len(e.ChecksumMismatches) > 0 {
-		s := "checksum mismatches:\n"
+		buf.Reset()
+		buf.WriteString("checksum mismatches:\n")
 		for _, m := range e.ChecksumMismatches {
-			s += m.Error() + "\n"
+			buf.WriteString(m.Error() + "\n")
 		}
-		segments = append(segments, s)
+		segments = append(segments, buf.String())
 	}
 	if len(e.DanglingIdentifiers) > 0 {
-		s := "dangling identifiers:\n"
+		buf.Reset()
+		buf.WriteString("dangling identifiers:\n")
 		for _, id := range e.DanglingIdentifiers {
-			s += Encode(id) + "\n"
+			buf.WriteString(Encode(id) + "\n")
 		}
-		segments = append(segments, s)
+		segments = append(segments, buf.String())
 	}
 	if len(e.DanglingStatus) > 0 {
-		s := "dangling status:\n"
+		buf.Reset()
+		buf.WriteString("dangling status:\n")
 		for _, id := range e.DanglingStatus {
-			s += Encode(id) + "\n"
+			buf.WriteString(Encode(id) + "\n")
 		}
-		segments = append(segments, s)
+		segments = append(segments, buf.String())
 	}
 	if len(e.Errs) > 0 {
-		s := "errors during scrub:\n"
+		buf.Reset()
+		buf.WriteString("errors during scrub:\n")
 		for pathname, errs := range e.errs {
-			s += "  " + pathname.Value() + ":\n"
+			buf.WriteString("  " + pathname.Value() + ":\n")
 			for _, err := range errs {
-				s += "    " + err.Error() + "\n"
+				buf.WriteString("    " + err.Error() + "\n")
 			}
 		}
-		segments = append(segments, s)
+		segments = append(segments, buf.String())
 	}
 	return strings.Join(segments, "\n")
 }