Support \noexpand in \MakeUpper/Lowercase

We need to ensure these survive the expander inside
the expl3 code, which is done most readily by suppressing
that code entirely using \unexpanded.

base/changes.txt

@@ -6,6 +6,12 @@ completeness or accuracy and it contains some references to files that
 are not part of the distribution.
 ================================================================================
 
+2022-04-21  Joseph Wright <Joseph.Wright@latex-project.org>
+
+	* ltfinal.dtx (subsection{Lccodes and uccodes}):
+	Support \noexpand in arg. to \MakeUppercase and
+	\MakeLowercase
+
 2022-04-08  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
 
 	* ltmath.dtx (subsubsection{The UNSORTED Rest}):

base/ltfinal.dtx

@@ -33,7 +33,7 @@
 %<*driver>
 % \fi
 \ProvidesFile{ltfinal.dtx}
-             [2022/04/03 v2.2s LaTeX Kernel (Final Settings)]
+             [2022/04/21 v2.2t LaTeX Kernel (Final Settings)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltfinal.dtx}
@@ -1104,14 +1104,15 @@
 % \changes{v2.1h}{2019/09/14}{Expand UTF8 chars when case changing (github/177)}
 % \changes{v2.2r}{2022/02/20}
 %                {Use \cs{@expl@text@uppercase@@n}, removing local redefinition of \cs{UTF@two@octets@noexpand}}%
+% \changes{v2.2t}{2022/04/21}{Support \cs{noexpand} in argument of \cs{@expl@text@uppercase@@n}}
 %    \begin{macrocode}
-      \protected@edef\reserved@a{\@expl@text@uppercase@@n{#1}}%
+      \protected@edef\reserved@a{\@expl@text@uppercase@@n{\noexpand\unexpanded{#1}}}%
       \reserved@a
    }}
 \DeclareRobustCommand{\MakeLowercase}[1]{{%
       \def\reserved@a##1##2{\let##2##1\reserved@a}%
       \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
-      \protected@edef\reserved@a{\@expl@text@lowercase@@n{#1}}%
+      \protected@edef\reserved@a{\@expl@text@lowercase@@n{\noexpand\unexpanded{#1}}}%
       \reserved@a
    }}
 %    \end{macrocode}