grilling: separate questions in a round with an HR

Multi-question rounds ran straight into each other with no visual
break. Fold the horizontal rule (---) directly into the round
template so consecutive questions are shown as distinct blocks; the
template demonstrates the separator, so no extra prose instruction
is needed.

.changeset/grilling-add-hr-between-questions.md

@@ -0,0 +1,5 @@
+---
+"mattpocock-skills": patch
+---
+
+grilling: update the round template so consecutive questions are separated by a horizontal rule (`---`) instead of running together.

skills/productivity/grilling/SKILL.md

@@ -7,11 +7,17 @@ Interview the user relentlessly until you reach a shared understanding. Map this
 
 Work the tree in **rounds**. The **frontier** is every decision whose prerequisites are already settled: the questions you can ask _now_ without guessing at answers you haven't heard yet. Ask the whole frontier in one round: number each question and give your recommended answer. Then wait for the user's answers before the next round.
 
-Each question should be formatted like so:
+Format a round like so:
 
 ```
 ❓ **Q1** - **<question title>**: <question body, might be multiple paragraphs, including multiple choices>
 
+➡️ <your recommended answer>
+
+---
+
+❓ **Q2** - **<question title>**: <question body, might be multiple paragraphs, including multiple choices>
+
 ➡️ <your recommended answer>
 ```