Add package management to tutorial and startup screen

* etc/tutorials/TUTORIAL: Add section about package installation.
* lisp/startup.el (fancy-startup-tail): Add button for
package-list-packages.

This was discussed in:
https://lists.gnu.org/r/emacs-devel/2021-12/msg00079.html

1 files changed, 14 insertions, 0 deletions

diff --git a/etc/tutorials/TUTORIAL b/etc/tutorials/TUTORIAL
index dcdb61f23ec..d7a298ed58a 100644
--- a/etc/tutorials/TUTORIAL
+++ b/etc/tutorials/TUTORIAL
@@ -1099,6 +1099,20 @@ manual in the node called "Dired".
 The manual also describes many other Emacs features.
 
 
+* INSTALLING PACKAGES
+---------------------
+
+Emacs has a rich set of packages written by the community, which
+extends Emacs' capabilities.  These features include support for new
+languages, additional themes, plugins for integrating with external
+applications and much much more.
+
+To see a list of all available packages, type M-x list-packages.  In
+this mode, you can install or uninstall packages, as well as read
+packages' descriptions.  For more information about package
+management, consult the manual.
+
+
 * CONCLUSION
 ------------