Cleanup cast_safe<void> specialization (#3861)

* Cleanup cast_safe<void> specialization

Replace explicit specialization of cast_safe<void> with SFINAE.
It's better for SFINAE cases to cover all type-sets rather than mixing SFINAE and explicit specialization.

Extracted from #3674

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update cast.h

Use detail::none_of<> as suggested

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update cast.h

Reorder:
If TEMP_REF
If VOID
if (!VOID && !TEMP_REF)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: laramiel

include/pybind11/cast.h

@@ -1155,15 +1155,18 @@ enable_if_t<!cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&,
 // static_assert, even though if it's in dead code, so we provide a "trampoline" to pybind11::cast
 // that only does anything in cases where pybind11::cast is valid.
 template <typename T>
-enable_if_t<!cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&o) {
-    return pybind11::cast<T>(std::move(o));
-}
-template <typename T>
 enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&) {
     pybind11_fail("Internal error: cast_safe fallback invoked");
 }
-template <>
-inline void cast_safe<void>(object &&) {}
+template <typename T>
+enable_if_t<std::is_same<void, intrinsic_t<T>>::value, void> cast_safe(object &&) {}
+template <typename T>
+enable_if_t<detail::none_of<cast_is_temporary_value_reference<T>,
+                            std::is_same<void, intrinsic_t<T>>>::value,
+            T>
+cast_safe(object &&o) {
+    return pybind11::cast<T>(std::move(o));
+}
 
 PYBIND11_NAMESPACE_END(detail)