Parts of the teaching document “Using signals“ zh_CH version are out of date

**Your Godot version:**
v4.0.2

**Issue description:**
The _ready() function is too old, [timer.connect("timeout", self, "_on_Timer_timeout")] can not run now, the English version is right, it should be [timer.timeout.connect(_on_Timer_timeout)].

**URL to the documentation page:**
https://docs.godotengine.org/zh_CN/stable/getting_started/step_by_step/signals.html

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