Replace custom line breaks in ListBlockRenderer

src/Renderer/Block/ListBlockRenderer.php

@@ -26,6 +26,8 @@ public function render(Node $node, ChildNodeRendererInterface $childRenderer): s
         $content = $childRenderer->renderNodes($node->children());
         $content = explode("\n", $content);
 
+        $content = array_map(fn ($item) => $this->replaceInternalLineBreakCharacter($item), $content);
+
         if ($listData->type === ListBlock::TYPE_BULLET) {
             $content = array_map(fn ($item) => "- {$item}", $content);
         }
@@ -42,4 +44,16 @@ public function render(Node $node, ChildNodeRendererInterface $childRenderer): s
 
         return implode("\n", $content) . "\n";
     }
+
+    /**
+     * Replace custom line break character with _native_ line breaks.
+     * Whitespace is added so that other Markdown clients correctly
+     * render the list and its line breaks.
+     * @param string $content
+     * @return string
+     */
+    private function replaceInternalLineBreakCharacter(string $content): string
+    {
+        return str_replace(ListItemRenderer::INLINE_LINE_BREAK, "   \n  ", $content);
+    }
 }