Track smart_holder PR #5286: Fix `HAVE` vs `HAS` naming mishap (`PYBIND11_HAS_INTERNALS_WITH_SMART_HOLDER_SUPPORT`)

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Track smart_holder PR #5286: Fix HAVE vs HAS naming mishap (PYBIND11_HAS_INTERNALS_WITH_SMART_HOLDER_SUPPORT)

https://github.com/pybind/pybind11/pull/5286

Systematic, trivial name change:

-PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT
+PYBIND11_HAS_INTERNALS_WITH_SMART_HOLDER_SUPPORT

This is for internal consistency. There are no PYBIND11_HAVE macros, but 10 unique PYBIND11_HAS macros:

$ git grep 'define PYBIND11_HAS' | sed 's/.*define PYBIND11_HAS/PYBIND11_HAS/' | cut -d' ' -f1 | sort | uniq

PYBIND11_HAS_EXPERIMENTAL_FILESYSTEM
PYBIND11_HAS_EXP_OPTIONAL
PYBIND11_HAS_FILESYSTEM
PYBIND11_HAS_FILESYSTEM_IS_OPTIONAL
PYBIND11_HAS_INTERNALS_WITH_SMART_HOLDER_SUPPORT
PYBIND11_HAS_OPTIONAL
PYBIND11_HAS_STD_LAUNDER
PYBIND11_HAS_STRING_VIEW
PYBIND11_HAS_U8STRING
PYBIND11_HAS_VARIANT