Revert "html: Export "#+HUGO: more" as <!--more-->"

This reverts commit 16a978fe48.

not needed after all - turns out hugo looks for the divider before rendering so
we can't do anything in go-org

org/html.go

@@ -169,11 +169,9 @@ func (w *HTMLWriter) writeDrawer(d Drawer) {
 	w.writeNodes(d.Children...)
 }
 
-func (w *HTMLWriter) writeKeyword(kw Keyword) {
-	if k, v := kw.Key, kw.Value; k == "HTML" {
-		w.WriteString(v + "\n")
-	} else if k == "HUGO" && v == "more" {
-		w.WriteString("<!--more-->\n")
+func (w *HTMLWriter) writeKeyword(k Keyword) {
+	if k.Key == "HTML" {
+		w.WriteString(k.Value + "\n")
 	}
 }
 

org/testdata/keywords.html

@@ -16,7 +16,3 @@ and an image with custom html attributes and a caption
 kittens!
 </figcaption>
 </figure>
-<p>
-This will be exported as &lt;!–more–&gt; just for hugo
-</p>
-<!--more-->

org/testdata/keywords.org

@@ -12,7 +12,3 @@ and an image with custom html attributes and a caption
 #+ATTR_HTML: :style height: 100%; :id overwritten
 #+ATTR_HTML: :style border: 10px solid black; :id kittens
 [[https://placekitten.com/200/200#.png]]
-
-
-This will be exported as <!--more--> just for hugo
-#+HUGO: more

org/testdata/keywords.pretty_org

@@ -12,7 +12,3 @@ and an image with custom html attributes and a caption
 #+ATTR_HTML: :style height: 100%; :id overwritten
 #+ATTR_HTML: :style border: 10px solid black; :id kittens
 [[https://placekitten.com/200/200#.png]]
-
-
-This will be exported as <!--more--> just for hugo
-#+HUGO: more