doc: 补全部分注释

pkg/core/boot.py

@@ -3,6 +3,8 @@ from __future__ import print_function
 from . import app
 from ..audit import identifier
 from . import stage
+
+# 引入启动阶段实现以便注册
 from .stages import load_config, setup_logger, build_app
 
 
@@ -20,6 +22,7 @@ async def make_app() -> app.Application:
 
     ap = app.Application()
 
+    # 执行启动阶段
     for stage_name in stage_order:
         stage_cls = stage.preregistered_stages[stage_name]
         stage_inst = stage_cls()