improve runtime events doc

xtask/res/templates/runtime-events.md

 # Runtime events
 
-There are xxx calls from **{{ pallets | length }}** pallets.
+There are **{{event_counter}}** events from **{{ pallets | length }}** pallets.
 
+<ul>
 {% for pallet in pallets -%}
-### {{ pallet.name }} - {{ pallet.index }}
-
+<li>{{ pallet.name }} - {{ pallet.index }}
+<ul>
 {% for event in pallet.events -%}
-#### {{ event.name }} - {{ event.index }}
-
-<details><summary><code>{{ event.name }}(
-    {%- for param in event.params -%}
-    {{ param.name }}{% if loop.last != true %}, {% endif %} 
-    {%- endfor -%}
-    )</code></summary>
+<li>
+<code>{{ event.name }}(
+{%- for param in event.params -%}
+{{ param.name }}{% if loop.last != true %}, {% endif %} 
+{%- endfor -%}
+)</code> - {{ event.index }}
+{% if event.params | length != 0 %}
+<details>
+<summary>args</summary>
 
 ```rust
 {% for param in event.params -%}
 {{ param.name }}: {{ param.type_name }}
 {% endfor -%}
 ```
-</details>
-
 
+</details>
+{% endif %}
+</li>
 {% endfor -%}
+</ul>
+</li>
 {% endfor -%}
+</ul>
\ No newline at end of file

xtask/src/gen_doc.rs

@@ -335,6 +335,11 @@ fn print_runtime(pallets: RuntimePallets) -> (String, String) {
         })
         .collect();
 
+    let mut event_counter = 0;
+    pallets
+        .iter()
+        .for_each(|pallet| event_counter += pallet.events.len());
+
     // compile template
     let tera = match Tera::new(TEMPLATES_GLOB) {
         Ok(t) => t,
@@ -360,6 +365,7 @@ fn print_runtime(pallets: RuntimePallets) -> (String, String) {
     // render events
 
     context.insert("pallets", &pallets);
+    context.insert("event_counter", &event_counter);
     let event_doc = tera
         .render("runtime-events.md", &context)
         .expect("template error");