[gcc r13-4168] libstdc++: Fix Doxygen warning

[gcc r13-4168] libstdc++: Fix Doxygen warning

[Jonathan Wakely]

https://gcc.gnu.org/g:fca0f50b145048afda17f0f10ac968afe6be0fad

commit r13-4168-gfca0f50b145048afda17f0f10ac968afe6be0fad
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Nov 17 10:20:50 2022 +0000

    libstdc++: Fix Doxygen warning
    
    This fixes a Doxygen warning about a mismatched parameter name. The
    standard uses 'r' here, like the Doxygen comment, so use '__r' instead
    of '__e'.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/ptr_traits.h (pointer_traits::pointer_to): Rename
            parameter.

Diff:
---
 libstdc++-v3/include/bits/ptr_traits.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/include/bits/ptr_traits.h b/libstdc++-v3/include/bits/ptr_traits.h
index 71370ff4fc9..b46a1ac34c9 100644
--- a/libstdc++-v3/include/bits/ptr_traits.h
+++ b/libstdc++-v3/include/bits/ptr_traits.h
@@ -104,17 +104,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       /**
        *  @brief  Obtain a pointer to an object
        *  @param  __r  A reference to an object of type `element_type`
-       *  @return `pointer::pointer_to(__e)`
-       *  @pre `pointer::pointer_to(__e)` is a valid expression.
+       *  @return `pointer::pointer_to(__r)`
+       *  @pre `pointer::pointer_to(__r)` is a valid expression.
       */
       static pointer
-      pointer_to(element_type& __e)
+      pointer_to(element_type& __r)
 #if __cpp_lib_concepts
       requires requires {
-	{ pointer::pointer_to(__e) } -> convertible_to<pointer>;
+	{ pointer::pointer_to(__r) } -> convertible_to<pointer>;
       }
 #endif
-      { return pointer::pointer_to(__e); }
+      { return pointer::pointer_to(__r); }
     };
 
   // Do not define pointer_traits<P>::pointer_to if element type is void.