Update ceval_macros.h to comply with Pythons naming scheme

[thefeiter]

UnboundLocalError and UnboundFreeError use the term "variable" for something that is called a "name" in python. This can lead to confusion when getting this error.

This PR replaces the ocurance of "variable" with "name" in the error messagees of UnboundLocalError and UnboundFreeError.

[ghost]

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[Eclips4]

I'm -1 on this change.
As you can see, CI was failed due to failing tests, which depends on string representation of these exceptions.
It's also breaks backwards compatibility.

[bedevere-app]

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If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.