Adjust clone timeout error to suggest increasing timeout

There are far too many error reports regarding timeouts from migrations.
We should adjust error report to suggest increasing this timeout.

Ref go-gitea#20680

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/repository/repo.go

@@ -6,6 +6,7 @@ package repository
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -79,6 +80,9 @@ func MigrateRepositoryGitData(ctx context.Context, u *user_model.User,
 		Timeout:       migrateTimeout,
 		SkipTLSVerify: setting.Migrations.SkipTLSVerify,
 	}); err != nil {
+		if errors.Is(err, context.DeadlineExceeded) {
+			return repo, fmt.Errorf("Clone timed out. Consider increasing [git.timeout] MIGRATE in app.ini. Underlying Error: %w", err)
+		}
 		return repo, fmt.Errorf("Clone: %w", err)
 	}