docs: add tested rsynchl quickstart

docs/quickstart.rst

@@ -19,4 +19,32 @@ If you just want to try borg-import with minimal setup:
     python -m venv env
     source env/bin/activate
     pip install -e .
-    borg-import --help
+    borg-import --help
+
+Import rsync snapshots
+----------------------
+
+For example, if an rsync-with-hard-links backup stores one snapshot per
+directory::
+
+    /srv/rsync-backups/
+    |-- snapshot-2026-08-28/
+    `-- snapshot-2026-08-29/
+
+first initialize the destination repository, then import the snapshots::
+
+    borg init --encryption=repokey /srv/borg-repository
+    borg-import rsynchl /srv/rsync-backups /srv/borg-repository
+
+The repository path must be absolute (or a remote repository specification).
+``borg-import`` creates one archive per snapshot directory, using the directory
+name as the archive name and its modification time as the archive timestamp.
+Confirm the imported archives with::
+
+    borg list --short /srv/borg-repository
+
+During an import, each snapshot directory is temporarily renamed within the
+snapshot root so Borg's files cache can recognize unchanged files efficiently.
+The directory is moved back even if ``borg create`` fails. Test with a copy of
+your backup first, and make sure the destination has enough free space before
+importing a large backup set.