[BUG]: Possibly missing `#include <cstdint>` in the `pybind11.h` and `attr.h`

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What version (or hash if on master) of pybind11 are you using?

master

Problem description

Possibly missing #include <cstdint> in the pybind11.h and attr.h. The mentioned headers do use e.g. std::uint_16, but don't include <cstdint> standard header. It is not clear if that is an intended omission.

Reproducible example code

None.

Is this a regression? Put the last known working version here if it is.

Not a regression

Inspect pybind11.h and attr.h first, focusing on their uses of std::uint_16 and whether those headers directly include . Then use the project’s C++ build or test checks to verify the headers compile with their required includes; the issue is done when the include requirement is explicit and the checks pass.