Don't use   or   to separate the tags

Update the test to include the scenario where tags are used on
sub-headings which will be rendered as list items.

doc/ox-hugo-manual.org

@@ -1729,6 +1729,23 @@ These variables do not affect the tags set via keywords =#+hugo_tags=,
 property forms), because Org keywords and properties allow using the
 hyphen and space (/in "double-quoted strings"/) characters. So the
 underscores in these keywords remain untransformed on export.
+**** Sub-heading Tags
+Sub-heading tags are exported wrapped in HTML ~span~ tags to the right
+of the exported heading if ~org-export-with-tags~ is non-nil (default)
+or if ~#+options: tags:t~ is used.
+
+The ~span~ tags are best formatted using CSS. Here's one example:
+
+#+begin_src css
+.tag span {
+    background: lightgrey;
+    font-size: small;
+    padding: 0.1rem 0.2rem;
+    margin: 0.2rem;
+}
+#+end_src
+
+{{{test-search(subheading-tags)}}}
 **** More Examples
 - [[https://raw.githubusercontent.com/kaushalmodi/ox-hugo/main/test/site/content-org/tags-and-categories.org][Org source]]
 - Exported Markdown -- [[https://raw.githubusercontent.com/kaushalmodi/ox-hugo/main/test/site/content/posts/inheriting-tags.md][=inheriting-tags.md=]], [[https://raw.githubusercontent.com/kaushalmodi/ox-hugo/main/test/site/content/posts/overriding-tags.md][=overriding-tags.md=]]

ox-hugo.el

@@ -1723,6 +1723,22 @@ user has requested for it.)"
          (member lang-2chars '("zh"      ;"zh", "zh_CH", ..
                                "ja"))))) ;"ja", ..
 
+(defun org-hugo--tags (tags info)
+  "Format TAGS into HTML.
+INFO is a plist containing export options.
+
+This function is almost identical to `org-html--tags' from
+`ox-html' except that the tag separator is an empty string."
+  (when tags
+    (format "<span class=\"tag\">%s</span>"
+            (mapconcat
+             (lambda (tag)
+               (format "<span class=\"%s\">%s</span>"
+                       (concat (plist-get info :html-tag-class-prefix)
+                               (org-html-fix-class-name tag))
+                       tag))
+             tags ""))))
+
 
 
 ;;; Transcode Functions
@@ -1861,7 +1877,7 @@ a communication channel."
                            (let* ((tags-list (org-export-get-tags heading info))
                                   (tags-list (dolist (fn org-hugo-tag-processing-functions tags-list)
                                                (setq tags-list (funcall fn tags-list info))))
-                                  (tags-html (org-html--tags tags-list info)))
+                                  (tags-html (org-hugo--tags tags-list info)))
                              (when (org-string-nw-p tags-html)
                                (concat " " tags-html)))))
            (priority

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

@@ -538,16 +538,19 @@ Export the SCHEDULED, DEADLINE, etc. planning info time stamps.
 {{{oxhugoissue(514)}}}
 *** TODO Some plan
 SCHEDULED: <2022-01-20 Mon> DEADLINE: <2022-01-30 Mon>
-** Export with sub-heading tags                                :tags:subtree:
+** Export with sub-heading tags                        :tags:subheading_tags:
 :PROPERTIES:
 :EXPORT_FILE_NAME: sub-headings-with-tags
-:EXPORT_OPTIONS: tags:t
+:EXPORT_OPTIONS: tags:t h:2
 :END:
 #+begin_description
 Export tags of sub-headings
 #+end_description
 {{{oxhugoissue(513)}}}
-*** Sub heading                              :abc:def:@abc__def__ghi:ghi_jkl:
+*** Sub heading level 1                      :abc:def:@abc__def__ghi:ghi_jkl:
+**** Sub heading level 2                     :abc:def:@abc__def__ghi:ghi_jkl:
+***** Sub heading level 3                    :abc:def:@abc__def__ghi:ghi_jkl:
+****** Sub heading level 4                   :abc:def:@abc__def__ghi:ghi_jkl:
 * Title in Front Matter                                               :title:
 ** Awesome title with "quoted text"
 :PROPERTIES:

test/site/content/posts/sub-headings-with-tags.md

@@ -1,11 +1,22 @@
 +++
 title = "Export with sub-heading tags"
 description = "Export tags of sub-headings"
-tags = ["headings", "tags", "subtree"]
+tags = ["headings", "tags", "subheading-tags"]
 draft = false
 +++
 
 `ox-hugo` Issue #[513](https://github.com/kaushalmodi/ox-hugo/issues/513)
 
 
-## Sub heading <span class="tag"><span class="abc">abc</span>&#xa0;<span class="def">def</span>&#xa0;<span class="_abc_def_ghi">@abc def ghi</span>&#xa0;<span class="ghi_jkl">ghi-jkl</span></span> {#sub-heading}
+## Sub heading level 1 <span class="tag"><span class="abc">abc</span><span class="def">def</span><span class="_abc_def_ghi">@abc def ghi</span><span class="ghi_jkl">ghi-jkl</span></span> {#sub-heading-level-1}
+
+
+### Sub heading level 2 <span class="tag"><span class="abc">abc</span><span class="def">def</span><span class="_abc_def_ghi">@abc def ghi</span><span class="ghi_jkl">ghi-jkl</span></span> {#sub-heading-level-2}
+
+<!--list-separator-->
+
+-  Sub heading level 3 <span class="tag"><span class="abc">abc</span><span class="def">def</span><span class="_abc_def_ghi">@abc def ghi</span><span class="ghi_jkl">ghi-jkl</span></span>
+
+    <!--list-separator-->
+
+    -  Sub heading level 4 <span class="tag"><span class="abc">abc</span><span class="def">def</span><span class="_abc_def_ghi">@abc def ghi</span><span class="ghi_jkl">ghi-jkl</span></span>