Formatting: Ignore chat separators with markdown

Some chat separators (or dinkuses) cause markdown to be rendered
on the chat window.

Examples include "###" -> h3 and "---" -> metadata.

This can look jarring to the end user as it can interrupt a pleasant
chat experience. Therefore, it makes sense to ignore these lines with
div tags that indicate to Showdown that this string doesn't need markdown.

Signed-off-by: kingbri <bdashore3@proton.me>

public/scripts/power-user.js

@@ -933,6 +933,7 @@ $(document).ready(() => {
     $("#custom_chat_separator").on('input', function () {
         power_user.custom_chat_separator = $(this).val();
         saveSettingsDebounced();
+        reloadMarkdownProcessor(power_user.render_formulas);
     });
 
     $("#multigen").change(function () {