meson: restore hook-list.h to builtin_sources

meson: restore hook-list.h to builtin_sources

This fixes a racy build failure.

```
builtin/bugreport.c:12:10: fatal error: hook-list.h: No such file or directory
   12 | #include "hook-list.h"
      |          ^~~~~~~~~~~~~

```

hook-list.h must be generated before builtin/bugreport.c is compiled.

Bug: https://bugs.gentoo.org/978326
Fixes: 2eb541e8f2a9 (hook: move is_known_hook() to hook.c for wider use, 2026-04-10)
Signed-off-by: Mike Gilbert <redacted>
Acked-by: Patrick Steinhardt <redacted>
Signed-off-by: Junio C Hamano <redacted>