[gcc r16-8425] libstdc++: Simplify documentation of match_flag_type::format_default

[Jonathan Wakely]

https://gcc.gnu.org/g:74b665e0f0fed9e544cf332089ee7abad528aa93

commit r16-8425-g74b665e0f0fed9e544cf332089ee7abad528aa93
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 1 15:02:06 2026 +0100

    libstdc++: Simplify documentation of match_flag_type::format_default
    
    This combines the $n and $nn items into one, which is more consistent
    with the EcmaScript docs.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/regex_constants.h (format_default): Simplify
            description of $n in Doxygen comment.
    
    Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>

Diff:
---
 libstdc++-v3/include/bits/regex_constants.h | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/libstdc++-v3/include/bits/regex_constants.h b/libstdc++-v3/include/bits/regex_constants.h
index e18f162196e3..5fa78e18a3f1 100644
--- a/libstdc++-v3/include/bits/regex_constants.h
+++ b/libstdc++-v3/include/bits/regex_constants.h
@@ -339,14 +339,10 @@ namespace regex_constants
    *         This would be match_results::prefix().
    * @li $'  The portion of the string that follows the matched substring.
    *         This would be match_results::suffix().
-   * @li $n  The nth capture, where n is in [1,9] and $n is not followed by a
-   *         decimal digit.  If n <= match_results::size() and the nth capture
-   *         is undefined, use the empty string instead.  If n >
-   *         match_results::size(), the result is implementation-defined.
-   * @li $nn The nnth capture, where nn is a two-digit decimal number on
-   *         [01, 99].  If nn <= match_results::size() and the nth capture is
-   *         undefined, use the empty string instead. If
-   *         nn > match_results::size(), the result is implementation-defined.
+   * @li $n  The nth capture, where n is a positive integer less than 100.
+   *         If `n <= match_results::size()` and the nth capture is undefined,
+   *         use the empty string instead.  If `n > match_results::size()`,
+   *         the result is implementation-defined.
    */
   _GLIBCXX17_INLINE constexpr match_flag_type format_default = _S_default;