[gcc r16-8099] libstdc++: Fix Doxygen @since comment in <text_encoding>

[Jonathan Wakely]

https://gcc.gnu.org/g:063979dc0b5cd5e0461bd0d925902392c5ad7cb6

commit r16-8099-g063979dc0b5cd5e0461bd0d925902392c5ad7cb6
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Sat Mar 14 00:27:16 2026 +0000

    libstdc++: Fix Doxygen @since comment in <text_encoding>
    
    This is a C++26 feature, not C++23.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/text_encoding: Fix @since in Doxygen comment.

Diff:
---
 libstdc++-v3/include/std/text_encoding | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/std/text_encoding b/libstdc++-v3/include/std/text_encoding
index 6fcaed1ab6aa..8b5e6cc5a9a1 100644
--- a/libstdc++-v3/include/std/text_encoding
+++ b/libstdc++-v3/include/std/text_encoding
@@ -38,7 +38,7 @@
 #define __glibcxx_want_text_encoding
 #include <bits/version.h>
 
-#ifdef __cpp_lib_text_encoding
+#ifdef __cpp_lib_text_encoding // >= C++26
 #include <compare>
 #include <string_view>
 #include <bits/functional_hash.h> // hash
@@ -53,7 +53,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /**
    * @brief An interface for accessing the IANA Character Sets registry.
    * @ingroup locales
-   * @since C++23
+   * @since C++26
    */
   struct text_encoding
   {