Add new filter command to Package Menu (Bug#39903)

* lisp/emacs-lisp/package.el
(package-menu-filter-marked): New filter command.
* test/lisp/emacs-lisp/package-tests.el
(package-test-list-filter-marked): New test.
(package-menu-mode-menu):
(package-menu-mode-map): Update menu to include new filter command.

* doc/emacs/package.texi (Package Menu): Document the new command.
* etc/NEWS: Announce the new command.

1 files changed, 6 insertions, 0 deletions

diff --git a/doc/emacs/package.texi b/doc/emacs/package.texi
index db3cf317ff1..91e44b8eba8 100644
--- a/doc/emacs/package.texi
+++ b/doc/emacs/package.texi
@@ -202,6 +202,12 @@ This prompts first for one of the qualifiers @samp{<}, @samp{>} or
 @samp{=}, and then a package version, and shows packages that has a
 lower, equal or higher version than the one specified.
 
+@item / m
+@kindex / m @r{(Package Menu)}
+@findex package-menu-filter-marked
+Filter package list by non-empty mark (@code{package-menu-filter-marked}).
+This shows only the packages that have been marked to be installed or deleted.
+
 @item / /
 @kindex / / @r{(Package Menu)}
 @findex package-menu-filter-clear