e2scrub: add missing Documentation links to systemd unit files

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/scrub/e2scrub_fail@.service.in b/scrub/e2scrub_fail@.service.in
index df87949..ffc296a 100644
--- a/scrub/e2scrub_fail@.service.in
+++ b/scrub/e2scrub_fail@.service.in
@@ -1,5 +1,6 @@
 [Unit]
 Description=Online ext4 Metadata Check Failure Reporting for %I
+Documentation=man:e2scrub(8)
 
 [Service]
 Type=oneshot
diff --git a/scrub/e2scrub_reap.service.in b/scrub/e2scrub_reap.service.in
index 8a32077..b053615 100644
--- a/scrub/e2scrub_reap.service.in
+++ b/scrub/e2scrub_reap.service.in
@@ -1,5 +1,6 @@
 [Unit]
 Description=Remove Stale Online ext4 Metadata Check Snapshots
+Documentation=man:e2scrub_all(8)
 
 [Service]
 Type=oneshot