fix(docs): Minor update to esp_event.rst for improved user experience

This commit adds semicolons in c-code blocks in esp_event.rst for
improved user experience when directly copying and pasting code.

Closes #13156

docs/en/api-reference/system/esp_event.rst

@@ -100,13 +100,13 @@ Event base declaration:
 
 .. code-block:: c
 
-    ESP_EVENT_DECLARE_BASE(EVENT_BASE)
+    ESP_EVENT_DECLARE_BASE(EVENT_BASE);
 
 Event base definition:
 
 .. code-block:: c
 
-    ESP_EVENT_DEFINE_BASE(EVENT_BASE)
+    ESP_EVENT_DEFINE_BASE(EVENT_BASE);
 
 .. note::