chore: Follow up linebreaks in html rendering

lib/pages/chat/events/html_message.dart

@@ -83,21 +83,25 @@ class HtmlMessage extends StatelessWidget {
   /// We add line breaks before these tags:
   static const Set<String> blockHtmlTags = {
     'p',
-    'h1',
-    'h2',
-    'h3',
-    'h4',
-    'h5',
-    'h6',
     'ul',
     'ol',
-    'li',
     'pre',
     'br',
     'div',
     'table',
-    'blockquote',
     'details',
+    'blockquote',
+  };
+
+  /// We add line breaks before these tags:
+  static const Set<String> fullLineHtmlTag = {
+    'h1',
+    'h2',
+    'h3',
+    'h4',
+    'h5',
+    'h6',
+    'li',
   };
 
   /// Adding line breaks before block elements.
@@ -105,17 +109,24 @@ class HtmlMessage extends StatelessWidget {
     dom.NodeList nodes,
     BuildContext context, {
     int depth = 1,
-  }) =>
-      [
-        for (var i = 0; i < nodes.length; i++) ...[
-          if (i > 0 &&
-              nodes[i] is dom.Element &&
-              blockHtmlTags.contains((nodes[i] as dom.Element).localName))
-            const TextSpan(text: '\n'), // Add linebreak
-          // Actually render the node child:
-          _renderHtml(nodes[i], context, depth: depth + 1),
+  }) {
+    final onlyElements = nodes.whereType<dom.Element>().toList();
+    return [
+      for (var i = 0; i < nodes.length; i++) ...[
+        // Actually render the node child:
+        _renderHtml(nodes[i], context, depth: depth + 1),
+        // Add linebreaks between blocks:
+        if (nodes[i] is dom.Element &&
+            onlyElements.indexOf(nodes[i] as dom.Element) <
+                onlyElements.length - 1) ...[
+          if (blockHtmlTags.contains((nodes[i] as dom.Element).localName))
+            const TextSpan(text: '\n\n'),
+          if (fullLineHtmlTag.contains((nodes[i] as dom.Element).localName))
+            const TextSpan(text: '\n'),
         ],
-      ];
+      ],
+    ];
+  }
 
   /// Transforms a Node to an InlineSpan.
   InlineSpan _renderHtml(
@@ -144,6 +155,8 @@ class HtmlMessage extends StatelessWidget {
     if (!allowedHtmlTags.contains(node.localName)) return const TextSpan();
 
     switch (node.localName) {
+      case 'br':
+        return const TextSpan(text: '\n');
       case 'a':
         final href = node.attributes['href'];
         if (href == null) continue block;