[mdspan.layout.leftpad.obs] Remove superfluous \item (#6944)

Author: Andreas-Krug

source/containers.tex

@@ -21485,7 +21485,6 @@
 \item
 \tcode{(is_convertible_v<Indices, index_type> \&\& ...)} is \tcode{true}.
 \item
-\item
 \tcode{(is_nothrow_constructible_v<index_type, Indices> \&\& ...)} is \tcode{true}.
 \end{itemize}