LWG4443 Clean up identifier comparisons in meta::define_aggregate

Fixes NB US 127-190 (C++26 CD).

Author: burblebee

source/meta.tex

@@ -6627,9 +6627,9 @@
   then either:
   \begin{itemize}
   \item
-    \tcode{$N_K$ != $N_L$} is \tcode{true} or
+    $N_K$ is not the same identifier as $N_L$ or
   \item
-    \tcode{$N_K$ == u8"_"} is \tcode{true}.
+    $N_K$ is the identifier \tcode{_} (\ucode{005f} low line).
     \begin{note}
     Every provided identifier is unique or \tcode{"_"}.
     \end{note}
@@ -6665,7 +6665,7 @@
     If $N_K$ is $\bot$,
     $M_K$ is an unnamed bit-field.
     Otherwise, $M_K$ is a non-static data member whose name is the identifier
-    determined by the character sequence encoded by $N_K$ in UTF-8.
+    $N_K$.
   \item
     The type of $M_K$ is $T_K$.
   \item