add block tag leakage warning for .Summary

Read more gohugoio/hugo#14044

Author: imomaliev

content/en/methods/page/Summary.md

@@ -25,6 +25,9 @@ To list the pages in a section with a summary beneath each link:
 {{ end }}
 ```
 
+> [!warning]
+> `.Summary` may cut block tags like (`blockquote`) in the middle, leading to end-tag recovery by the browser (the end tag will be added before parent's end tag), causing unexpected rendering behaviour. To avoid that wrap `.Summary` usage with `article` or `section` tags.
+
 Depending on content length and how you define the summary, the summary may be equivalent to the content itself. To determine whether the content length exceeds the summary length, use the [`Truncated`] method on a `Page` object. This is useful for conditionally rendering a “read more” link:
 
 ```go-html-template