Mention undo-amalgamate-change-group in the lispref manual

* doc/lispref/text.texi (Atomic Changes): Mention
undo-amalgamate-change-group (bug#42303).

(cherry picked from commit ba25a82855a2c03c25fec83f3056c166b692e94f)

1 files changed, 5 insertions, 0 deletions

diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index 06975f76706..5eead42031d 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -5561,6 +5561,11 @@ This function cancels and undoes all the changes in the change group
 specified by @var{handle}.
 @end defun
 
+@defun undo-amalgamate-change-group
+Amalgamate changes in change-group since @var{handle}.  I.e., remove
+all undo boundaries between the state of @var{handle} and now.
+@end defun
+
   Your code should use @code{unwind-protect} to make sure the group is
 always finished.  The call to @code{activate-change-group} should be
 inside the @code{unwind-protect}, in case the user types @kbd{C-g}