ws trimming: Fix case where there's a > char before trimmed block

doc/ox-hugo-manual.org

@@ -3150,6 +3150,7 @@ will export as:
 
 and render as:
 
+#+header: :trim-pre nil
 #+begin_mark
 This sentence is marked.
 #+end_mark

ox-hugo.el

@@ -1852,9 +1852,17 @@ holding export options."
                        (> toc-level 0)) ;TOC will be exported only if toc-level is positive
                   (concat (org-hugo--build-toc info toc-level) "\n")
                 ""))
-         (contents (replace-regexp-in-string ;Trim stuff before selected exported elements
-                    (concat "\\([[:space:]>]\\|\n\\)+" (regexp-quote org-hugo--trim-pre-marker))
-                    "\n" contents))
+         ;; Handling the case of special blocks inside markdown quote
+         ;; blocks.
+         (contents (replace-regexp-in-string
+                    (concat "\\(\n> \\)*" (regexp-quote org-hugo--trim-pre-marker))
+                    ;;          ^^ Markdown quote blocks have lines beginning with "> ".
+                    org-hugo--trim-pre-marker ;Keep the trim marker; it will be removed next.
+                    contents))
+         (contents (replace-regexp-in-string
+                    (concat "\\([[:space:]]\\|\n\\)*" (regexp-quote org-hugo--trim-pre-marker))
+                    "\n"
+                    contents))
          (contents (replace-regexp-in-string ;Trim stuff after selected exported elements
                     (concat (regexp-quote org-hugo--trim-post-marker) "\\([[:space:]>]\\|\n\\)+")
                     "\n" contents))

test/site/content-org/all-posts.org

@@ -4922,6 +4922,18 @@ something
 #+begin_mark
 marked text
 #+end_mark
+**** ~>~ character before a special block with ~:trim_pre~ set
+#+begin_export html
+<style>
+  .red {
+    color: red;
+  }
+</style>
+#+end_export
+#+attr_html: :class red
+#+begin_mark
+This marked text's foreground is red.
+#+end_mark
 **** Last element of a post
 #+begin_mark
 No "post" trim markers should be inserted after this block as it's the

test/site/content/posts/ws-trimming-around-special-blocks-corner-cases.md

@@ -53,6 +53,16 @@ something
 <mark>marked text</mark>
 
 
+## `>` character before a special block with `:trim_pre` set {#character-before-a-special-block-with-trim-pre-set}
+
+<style>
+  .red {
+    color: red;
+  }
+</style>
+<mark class="red">This marked text's foreground is red.</mark>
+
+
 ## Last element of a post {#last-element-of-a-post}
 <mark>No "post" trim markers should be inserted after this block as it's the
 last element of this post.</mark>