[clang] [clang][StaticAnalyzer] fix function evalCall() typo in CheckerDocumentation (PR #83677)

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mzyKi wrote:

> Makes sense, but how did it build before the fix? I thought by inheriting from `Checker` it would take the address of the member function with the expected signature to store them inside vectors. How could it take the address of a nonexisting member function?
I think ```evalCall()``` is an independent function in CheckerDocumentation.cpp and it has no relation with ```Checker<eval::Call>```. If no problem, I will merge soon.

https://github.com/llvm/llvm-project/pull/83677