Add IWYU pragma to base.h

[HazardyKnusperkeks]

So clang-tidy is happy if you include <fmt/format.h> for fmt::formatter.

[vitaut]

Thanks for the PR but I don't think it is correct to mark fmt/base.h as a private header in general. Even you consider just fmt::formatter, fmt/base.h is the header that defines it. You only need to include fmt/format.h or other headers like fmt/std.h if you need specializations defined in those headers.

[HazardyKnusperkeks]

I never considered fmt/base.h to be part of the API. But if it is, then everything is fine. Thanks.

[mwinterberg-dtek]

https://github.com/include-what-you-use/include-what-you-use/blob/master/docs/IWYUPragmas.md#iwyu-pragma-export

would annotating the "base.h" include with export make everyone happy?

[HazardyKnusperkeks]

I'm happy. ;) If clang-tidy would be happy, I don't know.