[gcc r13-2697] libstdc++: Fix Doxygen commands

[gcc r13-2697] libstdc++: Fix Doxygen commands

[Jonathan Wakely]

https://gcc.gnu.org/g:64f9580423eef22b81a7e90be851c81dc6e04778

commit r13-2697-g64f9580423eef22b81a7e90be851c81dc6e04778
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Sep 16 11:36:41 2022 +0100

    libstdc++: Fix Doxygen commands
    
    Remove the bogus -D__allocator_base=std::__new_allocator macro
    definition for Doxygen, because that's an alias template for C++11 and
    later, not a macro.
    
    Fix the @cond/@endcond pair that span the end of an @addtogroup group.
    Add another @endcond inside the group, and another @cond after it.
    
    libstdc++-v3/ChangeLog:
    
            * doc/doxygen/user.cfg.in (PREDEFINED): Remove __allocator_base.
            * include/bits/allocator.h: Fix nesting of Doxygen commands.

Diff:
---
 libstdc++-v3/doc/doxygen/user.cfg.in  | 1 -
 libstdc++-v3/include/bits/allocator.h | 3 +++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/doc/doxygen/user.cfg.in b/libstdc++-v3/doc/doxygen/user.cfg.in
index 57270bdeb7a..834ad9e4fd5 100644
--- a/libstdc++-v3/doc/doxygen/user.cfg.in
+++ b/libstdc++-v3/doc/doxygen/user.cfg.in
@@ -2407,7 +2407,6 @@ PREDEFINED             = __cplusplus=202002L \
                          _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED \
                          _GLIBCXX_HAVE_BUILTIN_LAUNDER \
 			 "_GLIBCXX_DOXYGEN_ONLY(X)=X " \
-			 __allocator_base=std::__new_allocator \
 			 __exception_ptr=__unspecified__ \
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
diff --git a/libstdc++-v3/include/bits/allocator.h b/libstdc++-v3/include/bits/allocator.h
index aec0b374fd1..28abf13eba9 100644
--- a/libstdc++-v3/include/bits/allocator.h
+++ b/libstdc++-v3/include/bits/allocator.h
@@ -265,6 +265,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef _Tp value_type;
       template<typename _Up> allocator(const allocator<_Up>&) { }
     };
+  /// @endcond
 
   /// @} group allocator
 
@@ -278,6 +279,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Undefine.
 #undef __allocator_base
 
+  /// @cond undocumented
+
   // To implement Option 3 of DR 431.
   template<typename _Alloc, bool = __is_empty(_Alloc)>
     struct __alloc_swap