gh-126107: Remove copyright block from Modules/config.c.in

[donBarbos]

Based on the last message I decided to make the this changes:

• COPYRIGHT file not found #126107 (comment)

• Issue: COPYRIGHT file not found #126107

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[StanFromIreland]

@gvanrossum This was originally your suggestion, what do you think? This PR which in my opinion is ready to merge as it completes the simple task has been forgotten about.

[gvanrossum]

While I think there are a lot more important things that could be done to this file (it's too slow and I suspect it tests for a lot of compiler features that are always supported by C compilers that can compile CPython), (and I suspect that you are sending this PR so can claim to have contributed to CPython on your resume :-), this is clearly the right thing to do, so I'll merge it.