Update simplified_chinese.txt

[Kyxnir]

improve consistency, add missing items, slightly enhance readability

Checklist

(it's just a translation update)

• Tested the change ingame
• Provided screenshots if it is a visual change
• Tested in combination with possibly related configuration options
• Written a unit test (especially base/) or added coverage to integration test
• Considered possible null pointers and out of bounds array indexing
• Changed no physics that affect existing maps
• Tested the change with ASan+UBSan or valgrind's memcheck (optional)

[Kyxnir]

No worries found out where to change it
If you see this message, please help me add my IGN EdEnd to the authors list. <3

[SollyBunny]

Aha i don't know chinese unfortunatley so I'm blidning trusting you here :P