Allow setting alternative key names for tags and categories

New keywords/properties:

    #+HUGO_FRONT_MATTER_KEY_ORG_TAGS
    :EXPORT_HUGO_FRONT_MATTER_KEY_ORG_TAGS:

    #+HUGO_FRONT_MATTER_KEY_ORG_CATEGORIES
    :EXPORT_HUGO_FRONT_MATTER_KEY_ORG_CATEGORIES:

Add test cases / examples for this new feature.

ox-hugo.el

@@ -663,6 +663,8 @@ newer."
                    (:hugo-auto-set-lastmod "HUGO_AUTO_SET_LASTMOD" nil org-hugo-auto-set-lastmod)
                    (:hugo-custom-front-matter "HUGO_CUSTOM_FRONT_MATTER" nil nil)
                    (:hugo-blackfriday "HUGO_BLACKFRIDAY" nil nil)
+                   (:hugo-front-matter-key-org-tags "HUGO_FRONT_MATTER_KEY_ORG_TAGS" nil "tags")
+                   (:hugo-front-matter-key-org-categories "HUGO_FRONT_MATTER_KEY_ORG_CATEGORIES" nil "categories")
 
                    ;; Front matter variables
                    ;; https://gohugo.io/content-management/front-matter/#front-matter-variables
@@ -2227,6 +2229,8 @@ INFO is a plist used as a communication channel."
          (all-t-and-c-str (org-entry-get (point) "ALLTAGS"))
          (all-t-and-c (when (stringp all-t-and-c-str)
                         (org-split-string all-t-and-c-str ":")))
+         (tags-key (intern
+                    (plist-get info :hugo-front-matter-key-org-tags)))
          (tags (or
                 ;; Look for tags set using #+HUGO_TAGS keyword, or
                 ;; EXPORT_HUGO_TAGS property if available.
@@ -2238,6 +2242,8 @@ INFO is a plist used as a communication channel."
                        (tags-list (org-hugo--transform-org-tags tags-list info)))
                   ;; (message "[get fm DBG] tags: tags-list = %S" tags-list)
                   tags-list)))
+         (categories-key (intern
+                          (plist-get info :hugo-front-matter-key-org-categories)))
          (categories (or
                       ;; Look for categories set using
                       ;; #+HUGO_CATEGORIES keyword, or
@@ -2297,8 +2303,8 @@ INFO is a plist used as a communication channel."
                  (markup . ,(org-export-data (plist-get info :hugo-markup) info))
                  (outputs . ,outputs)
                  (slug . ,(org-export-data (plist-get info :hugo-slug) info))
-                 (tags . ,tags)
-                 (categories . ,categories)
+                 (,tags-key . ,tags)
+                 (,categories-key . ,categories)
                  (type . ,(org-export-data (plist-get info :hugo-type) info))
                  (url . ,(org-export-data (plist-get info :hugo-url) info))
                  (weight . ,weight)
@@ -2319,6 +2325,8 @@ INFO is a plist used as a communication channel."
     ;; (message "[custom fm data DBG] %S" custom-fm-data)
     ;; (message "[fm resources OUT DBG] %S" resources)
     ;; (message "[fm data DBG] %S" data)
+    ;; (message "[fm tags key DBG] %s" tags-key)
+    ;; (message "[fm categories key DBG] %s" categories-key)
     ;; (message "[fm tags DBG] %S" tags)
     ;; (message "[fm categories DBG] %S" categories)
     (org-hugo--gen-front-matter data fm-format)))

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

@@ -3726,6 +3726,21 @@ This post has 1 author.
 :END:
 This post has multiple authors. In Org, multiple authors are added
 comma-separated.
+** Alternative front-matter keys                           :alternative:keys:
+*** Alternative "tags" key                                             :tags:
+:PROPERTIES:
+:EXPORT_FILE_NAME: alternative-tags-key
+:EXPORT_HUGO_FRONT_MATTER_KEY_ORG_TAGS: keywords
+:END:
+This post will have the =tags= key in front-matter renamed to
+=keywords=.
+*** Alternative "categories" key                     :categories:@test_cat_x:
+:PROPERTIES:
+:EXPORT_FILE_NAME: alternative-categories-key
+:EXPORT_HUGO_FRONT_MATTER_KEY_ORG_CATEGORIES: cats
+:END:
+This post will have the =categories= key in front-matter renamed to
+=cats=.
 * Real Examples                                               :real_examples:
 :PROPERTIES:
 :EXPORT_HUGO_SECTION: real-examples

test/site/content/posts/alternative-categories-key.md

@@ -0,0 +1,9 @@
++++
+title = "Alternative \"categories\" key"
+tags = ["front-matter", "alternative", "keys", "categories"]
+cats = ["test-cat-x"]
+draft = false
++++
+
+This post will have the `categories` key in front-matter renamed to
+`cats`.

test/site/content/posts/alternative-tags-key.md

@@ -0,0 +1,8 @@
++++
+title = "Alternative \"tags\" key"
+keywords = ["front-matter", "alternative", "keys", "tags"]
+draft = false
++++
+
+This post will have the `tags` key in front-matter renamed to
+`keywords`.