feat(editor): s jumps to the subscription field

src/lib/components/editor/Editor.svelte

@@ -59,6 +59,7 @@
     ["m", "amount", "amount"],
     ["c", "category", "category"],
     ["b", "budget", "budget"],
+    ["s", "bill", "subscription"],
     ["#", "tags", "tags"],
     ["r", "notes", "notes"],
   ];

src/lib/components/editor/SplitBox.svelte

@@ -393,7 +393,12 @@
         />
       </Field>
       {#if withdrawal}
-        <Field error={err("bill_id")} for={id("bill")} label="Subscription">
+        <Field
+          error={err("bill_id")}
+          for={id("bill")}
+          keys={keyHint("s")}
+          label="Subscription"
+        >
           <RefField
             id={id("bill")}
             invalid={Boolean(err("bill_id"))}