Fix and enhance comment editor monospace toggle (#36181)

Fixes: https://github.com/go-gitea/gitea/issues/36175

1. Correctly apply setting on textareas spawned by comment edit
3. When changing the setting, apply it to all textareas on the current page

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/shared/combomarkdowneditor.tmpl

@@ -77,7 +77,7 @@
 			>{{.TextareaContent}}</textarea>
 		</text-expander>
 		<script>
-			if (localStorage?.getItem('markdown-editor-monospace') === 'true') {
+			if (window.localUserSettings.getBoolean('markdown-editor-monospace')) {
 				document.querySelector('.markdown-text-editor').classList.add('tw-font-mono');
 			}
 		</script>