fix restic_diff function

zsh/functions

@@ -184,7 +184,7 @@ function tailmail() {
 # Show the diff between the latest two snapshots of restic repository
 # https://forum.restic.net/t/how-can-i-see-the-delta-between-two-snapshots/5258/4
 function restic_diff() {
-    restic diff --no-lock $(restic snapshots --no-lock --json --latest 2|jq --raw-output '(map(.id) | join(" "))') "$@"
+    restic diff --no-lock $(restic snapshots --no-lock --json --latest 2 | jq --raw-output 'map(.id) | .[-2:] | join(" ")') "$@"
 }
 # show the n biggest files within a restic repo; default 10
 function restic_lsfs() {