[absl] Update documentation to reflect hash support for std::wstring,…

[absl] Update documentation to reflect hash support for std::wstring, std::u16string and std::u32stringstrings

PiperOrigin-RevId: 515726337
Change-Id: I08e184ec1f7169835c034ac45a7e87293dc53078

absl/hash/hash.h

@@ -110,9 +110,10 @@ ABSL_NAMESPACE_BEGIN
 //   * std::unique_ptr and std::shared_ptr
 //   * std::unique_ptr and std::shared_ptr
 //   * All string-like types including:
 //   * All string-like types including:
 //     * absl::Cord
 //     * absl::Cord
-//     * std::string
-//     * std::string_view (as well as any instance of std::basic_string that
-//       uses char and std::char_traits)
+//     * std::string (as well as any instance of std::basic_string that
+//       uses one of {char, wchar_t, char16_t, char32_t} and its associated
+//       std::char_traits)
+//     * std::string_view
 //  * All the standard sequence containers (provided the elements are hashable)
 //  * All the standard sequence containers (provided the elements are hashable)
 //  * All the standard associative containers (provided the elements are
 //  * All the standard associative containers (provided the elements are
 //    hashable)
 //    hashable)

absl/hash/internal/hash.h

@@ -516,14 +516,14 @@ H AbslHashValue(H hash_state, const std::shared_ptr<T>& ptr) {
 // the same character sequence. These types are:
 // the same character sequence. These types are:
 //
 //
 //  - `absl::Cord`
 //  - `absl::Cord`
-//  - `std::string` (and std::basic_string<char, std::char_traits<char>, A> for
-//      any allocator A)
+//  - `std::string` (and std::basic_string<T, std::char_traits<T>, A> for
+//      any allocator A and any T in {char, wchar_t, char16_t, char32_t})
 //  - `absl::string_view` and `std::string_view`
 //  - `absl::string_view` and `std::string_view`
 //
 //
-// For simplicity, we currently support only `char` strings. This support may
-// be broadened, if necessary, but with some caution - this overload would
-// misbehave in cases where the traits' `eq()` member isn't equivalent to `==`
-// on the underlying character type.
+// For simplicity, we currently support only strings built on `char`, `wchar_t`,
+// `char16_t`, or `char32_t`. This support may be broadened, if necessary, but
+// with some caution - this overload would misbehave in cases where the traits'
+// `eq()` member isn't equivalent to `==` on the underlying character type.
 template <typename H>
 template <typename H>
 H AbslHashValue(H hash_state, absl::string_view str) {
 H AbslHashValue(H hash_state, absl::string_view str) {
   return H::combine(
   return H::combine(