jujutsu: Modify configuration and usage to fit the latest version

.justfile

@@ -51,7 +51,7 @@ push:
     jj git fetch --all-remotes
 
 rebase revision="dev":
-    jj rebase -b 'all:heads(all()) & ~signed() &~@' -d {{ revision }}
+    jj rebase -b 'heads(all()) & ~signed() &~@' -d {{ revision }}
 
 alias s := switch
 alias u := update

home/modules/programs/jujutsu.nix

@@ -47,8 +47,8 @@ in {
             auto-track = "true";
             max-new-file-size = 0;
           };
-          core = {
-            fsmonitor = "watchman";
+          fsmonitor = {
+            backend = "watchman";
             watchman.register-snapshot-trigger = true;
           };
           user = {