Fix wording, docs and style inconsistencies per audit of 0139564

internal/git/changes.go

@@ -2,6 +2,7 @@ package git
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"strconv"
@@ -148,7 +149,7 @@ func stats(ctx context.Context, dir, base, tree string) ([]api.FileChange, error
 		f := api.FileChange{Status: status}
 		if status == api.Renamed {
 			if i+2 >= len(tokens) {
-				return nil, fmt.Errorf("truncated rename in name-status output")
+				return nil, errors.New("truncated rename in name-status output")
 			}
 			old := tokens[i+1]
 			f.OldPath = &old
@@ -156,7 +157,7 @@ func stats(ctx context.Context, dir, base, tree string) ([]api.FileChange, error
 			i += 2
 		} else {
 			if i+1 >= len(tokens) {
-				return nil, fmt.Errorf("truncated name-status output")
+				return nil, errors.New("truncated name-status output")
 			}
 			f.Path = tokens[i+1]
 			i++