quickstart docs: only borg compact frees disk space

docs/quickstart_example.rst.inc

@@ -50,10 +50,14 @@
 
     $ borg extract /path/to/repo::Monday
 
-7. Recover disk space by manually deleting the *Monday* archive::
+7. Delete the *Monday* archive (please note that this does **not** free repo disk space)::
 
     $ borg delete /path/to/repo::Monday
 
+8. Recover disk space by compacting the segment files in the repo::
+
+    $ borg compact /path/to/repo
+
 .. Note::
     Borg is quiet by default (it works on WARNING log level).
     You can use options like ``--progress`` or ``--list`` to get specific