example: add sample message (#62)

Author: WofWca

message_parser_wasm/example.html

@@ -43,7 +43,23 @@ <h3>Input</h3>
       id="input"
       style="width: calc(100% - 10px)"
       rows="10"
-    ></textarea>
+>Sample message.
+#sampleHashtag
+https://example.com/example
+[email protected]
+/example_bot_command
+
+The ones below only work in Markdown mode:
+
+[Example LabeledLink](https://example.com)
+Sample __bold text__
+**Sample bold _and italics and ~~StrikeThrough and [link and `InlineCode`](https://example.com)~~_ text**
+
+```python
+print("And, of course")
+print("A code block")
+```
+</textarea>
     <label for="parse_mode">Mode: </label>
     <select name="parse_mode" id="parse_mode">
       <option value="text">TEXT Only</option>