[gcc r16-1426] libstdc++: Fix mismatched @cond and @endcond in <type_traits>

[Jonathan Wakely]

https://gcc.gnu.org/g:606f25a2d6206dd8769e998164268f038ccd3424

commit r16-1426-g606f25a2d6206dd8769e998164268f038ccd3424
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jun 11 13:21:24 2025 +0100

    libstdc++: Fix mismatched @cond and @endcond in <type_traits>
    
    I messed up the Doxygen conditionals in r16-1077-gb32bf304793047.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/type_traits: Restore @cond and @endcond balance.

Diff:
---
 libstdc++-v3/include/std/type_traits | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index c8907fe4d382..abff9f880001 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1036,6 +1036,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct __is_array_unknown_bounds<_Tp[]>
     : public true_type
     { };
+  /// @endcond
 
   // Destructible and constructible type properties.
 
@@ -1046,6 +1047,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : public __bool_constant<__is_destructible(_Tp)>
     { };
 #else
+  /// @cond undocumented
+
   // In N3290 is_destructible does not say anything about function
   // types and abstract types, see LWG 2049. This implementation
   // describes function types as non-destructible and all complete