Add changes.txt and \changes entries

base/changes.txt

@@ -6,6 +6,11 @@ completeness or accuracy and it contains some references to files that
 are not part of the distribution.
 ================================================================================
 
+2021-08-30  Phelype Oleinik  <phelype.oleinik@latex-project.org>
+
+	* lthooks.dtx (subsection{Using the hook}):
+	Clean up after \UseOneTimeHook and prevent a second usage (gh/606).
+
 2021-08-30  Phelype Oleinik  <phelype.oleinik@latex-project.org>
 
 	* ltcmd.dtx (subsubsection{Copying a command and its internal structure}):

base/lthooks.dtx

@@ -31,8 +31,8 @@
 %%% From File: lthooks.dtx
 %
 %    \begin{macrocode}
-\def\lthooksversion{v1.0q}
-\def\lthooksdate{2021/08/27}
+\def\lthooksversion{v1.0r}
+\def\lthooksdate{2021/09/06}
 %    \end{macrocode}
 %
 %<*driver>
@@ -2974,7 +2974,9 @@
 \cs_new_protected:Npn \@@_gput_code:nnn #1 #2 #3
   {
 %    \end{macrocode}
-%    First check if the hook was used as a one-time hook:
+%   First check if the code should be executed immediately, rather than
+%   stored:
+% \changes{v1.0r}{2021/09/06}{Use dedicated conditional (gh/606)}
 %    \begin{macrocode}
     \@@_if_execute_immediately:nTF {#1}
       {#3}
@@ -4812,6 +4814,7 @@
 %   hook name, since \cs{hook_use:n} and \cs{hook_use_once:n} are
 %   documented to not trim spaces.
 %
+% \changes{v1.0r}{2021/09/06}{Clean up after \cs{UseOneTimeHook} (gh/606)}
 %    \begin{macrocode}
 \cs_new_protected:Npn \hook_use_once:n #1
   {
@@ -4836,6 +4839,7 @@
 %   code from being added to the hook.  \cs{@@_use_once_clear:n} then
 %   clears the hook so that any further call to \cs{hook_use:n} or
 %   \cs{hook_use_once:n} will expand to nothing.
+% \changes{v1.0r}{2021/09/06}{Clean up after \cs{UseOneTimeHook} (gh/606)}
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_use_once_set:n #1
   { \@@_tl_gset:cn { g_@@_#1_reversed_tl } { I } }
@@ -4859,6 +4863,7 @@
 %   \cs[no-index]{g_@@_\meta{hook}_reversed_tl} is |I|.  The gymnastics
 %   around \cs{if:w} is there to allow the |reversed| token list to be
 %   empty.
+% \changes{v1.0r}{2021/09/06}{Macro added (gh/606)}
 %    \begin{macrocode}
 \prg_new_conditional:Npnn \@@_if_execute_immediately:n #1 { F, TF }
   {