chore(license): update spdx id in docs

[chenrui333]

followup #26

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missed it in the first place

[ccmywish]

Thank you Rui @chenrui333 , 🤝

I'm not very familiar with license issues, so I need to consult you about it.

I'm not sure if it's "dual license" as people understand. And I admit the sentence this PR focused on is kind of misleading.

This project includes a file called ./include/xy.h, which is a common C lib file I write to help to make program chsrc.c and chsrc.h easily. I want to make the xy.h more permissive, so I can use it in other non-GPL-3.0-or-later projects

I want to make chsrc only GPL-3.0-or-later. and chsrc is based on the MIT licensed ./include/xy.h

So, according to my idea above, is my situation called dual licensed? Does the two licenses conflict?

[chenrui333]

I'm not sure if it's "dual license" as people understand. And I admit the sentence this PR focused on is kind of misleading.

it is not dual license, so that is reason why it should use and rather than or

technically, I would also split the license file into two and just contain the standard body from the license templates (it would also help github, but not fully), that means github would display two licenses rather than custom license for now (but not show the license semantics like and or or). Let me know if that makes better sense.

[ccmywish]

Well and clearly explained!

[chenrui333]

THanks @ccmywish! 🙌

you can see now, it looks a bit better :)