remove unneeded color group commands

ChangeLog

@@ -3,6 +3,8 @@ https://github.com/latex3/xcolor/issues
 
 History
 =======
+2024/09/29
+* remove definitions of color groups as they are already in the kernel.
 
 2024/09/17
 * unknown model error handled (issue #1)

xcolor.dtx

@@ -6191,11 +6191,13 @@
 %
 %
 % \subsubsection{Extra groups}
-% Turning on extra groups in the standard \LaTeX\ commands, so that color commands are scoped correctly.
 %
-% Like |\normalcolor|, the following five commands are defined in the kernel, with empty definitions (|\relax|).
+% Like |\normalcolor|, the following five commands are defined in the kernel. 
 % This means that they can be used to make macros in packages `color safe'.
-% The commands will not have any effect unless a user also uses a color package, when the `active definitions' here will take effect and keep color commands correctly scoped.
+% The extra groups have been made permanent in the \LaTeX{} kernel 2021 so
+% they are no longer redefined here.
+% The |\color@setgroup| will not have any effect unless a user also uses 
+% a color package, when the `active definition' here will take effect. 
 %
 % \begin{macro}{\color@setgroup}
 % This is to be used in contexts (e.g., `lrbox') where text is to be saved and used after some other, unknown, text that may contain color commands.
@@ -6209,31 +6211,19 @@
 % This is to be used at the start of contexts that may contain color commands, but where it is not necessary to save the current color.
 % Examples of this are in the box commands of \File{ltboxes.dtx} where user-supplied text is saved internally in a box between |\color@begingroup|, |\color@endgroup|, but the box is used before any other color commands could intervene.
 % A matching |\color@endgroup| should be used at the end of the text.
-%    \begin{macrocode}
-\let\color@begingroup\begingroup
-%    \end{macrocode}
 %  \end{macro}
 %
 %  \begin{macro}{\color@endgroup}
 % To be used to close the `group' started by one of the above two commands.
 % The |\endgraf| in its definition is required in the case of groups of text in vertical `par' mode, but doesn't do any harm in horizontal `LR' contexts.
-%    \begin{macrocode}
-\def\color@endgroup{\endgraf\endgroup}
-%    \end{macrocode}
 %  \end{macro}
 %
 %  \begin{macro}{\color@hbox}
 % To be used to open a `colored hbox'
-%    \begin{macrocode}
-\def\color@hbox{\hbox\bgroup\color@begingroup}
-%    \end{macrocode}
 %  \end{macro}
 %
 %  \begin{macro}{\color@vbox}
 % To be used to open a `colored hbox'
-%    \begin{macrocode}
-\def\color@vbox{\vbox\bgroup\color@begingroup}
-%    \end{macrocode}
 %  \end{macro}
 %
 %  \begin{macro}{\color@endbox}