Remove deadcode (#22245)

- Remove code that isn't being used.

Found this is my stash from a few weeks ago, not sure how I found this
in the first place.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/git/repo_attribute.go

@@ -9,8 +9,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"strconv"
-	"strings"
 
 	"code.gitea.io/gitea/modules/log"
 )
@@ -288,102 +286,6 @@ func (wr *nulSeparatedAttributeWriter) Close() error {
 	return nil
 }
 
-type lineSeparatedAttributeWriter struct {
-	tmp        []byte
-	attributes chan attributeTriple
-	closed     chan struct{}
-}
-
-func (wr *lineSeparatedAttributeWriter) Write(p []byte) (n int, err error) {
-	l := len(p)
-
-	nlIdx := bytes.IndexByte(p, '\n')
-	for nlIdx >= 0 {
-		wr.tmp = append(wr.tmp, p[:nlIdx]...)
-
-		if len(wr.tmp) == 0 {
-			// This should not happen
-			if len(p) > nlIdx+1 {
-				wr.tmp = wr.tmp[:0]
-				p = p[nlIdx+1:]
-				nlIdx = bytes.IndexByte(p, '\n')
-				continue
-			} else {
-				return l, nil
-			}
-		}
-
-		working := attributeTriple{}
-		if wr.tmp[0] == '"' {
-			sb := new(strings.Builder)
-			remaining := string(wr.tmp[1:])
-			for len(remaining) > 0 {
-				rn, _, tail, err := strconv.UnquoteChar(remaining, '"')
-				if err != nil {
-					if len(remaining) > 2 && remaining[0] == '"' && remaining[1] == ':' && remaining[2] == ' ' {
-						working.Filename = sb.String()
-						wr.tmp = []byte(remaining[3:])
-						break
-					}
-					return l, fmt.Errorf("unexpected tail %s", remaining)
-				}
-				_, _ = sb.WriteRune(rn)
-				remaining = tail
-			}
-		} else {
-			idx := bytes.IndexByte(wr.tmp, ':')
-			if idx < 0 {
-				return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
-			}
-			working.Filename = string(wr.tmp[:idx])
-			if len(wr.tmp) < idx+2 {
-				return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
-			}
-			wr.tmp = wr.tmp[idx+2:]
-		}
-
-		idx := bytes.IndexByte(wr.tmp, ':')
-		if idx < 0 {
-			return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
-		}
-
-		working.Attribute = string(wr.tmp[:idx])
-		if len(wr.tmp) < idx+2 {
-			return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
-		}
-
-		working.Value = string(wr.tmp[idx+2:])
-
-		wr.attributes <- working
-		wr.tmp = wr.tmp[:0]
-		if len(p) > nlIdx+1 {
-			p = p[nlIdx+1:]
-			nlIdx = bytes.IndexByte(p, '\n')
-			continue
-		} else {
-			return l, nil
-		}
-	}
-
-	wr.tmp = append(wr.tmp, p...)
-	return l, nil
-}
-
-func (wr *lineSeparatedAttributeWriter) ReadAttribute() <-chan attributeTriple {
-	return wr.attributes
-}
-
-func (wr *lineSeparatedAttributeWriter) Close() error {
-	select {
-	case <-wr.closed:
-		return nil
-	default:
-	}
-	close(wr.attributes)
-	close(wr.closed)
-	return nil
-}
-
 // Create a check attribute reader for the current repository and provided commit ID
 func (repo *Repository) CheckAttributeReader(commitID string) (*CheckAttributeReader, context.CancelFunc) {
 	indexFilename, worktree, deleteTemporaryFile, err := repo.ReadTreeToTemporaryIndex(commitID)