ox-html.el (org-html-scripts, org-html-style-default): Use defcustom

* ox-html.el (org-html-scripts, org-html-style-default): Turn
into configurable options.

etc/ORG-NEWS

@@ -109,6 +109,11 @@ By default ox-html now inlines webp images.
 
 This is the CSS class name to use for the top level content wrapper.
 
+*** You can now configure ~org-html-scripts~ and ~org-html-style-default~
+
+~org-html-scripts~ and ~org-html-style-default~ used to be constants,
+you can now configure them.
+
 *** Some faces now use fixed-pitch
 
 See https://orgmode.org/list/875z8njaol.fsf@protesilaos.com.

lisp/ox-html.el

@@ -232,7 +232,7 @@ property on the headline itself.")
     ("\\.\\.\\." . "…"))		; hellip
   "Regular expressions for special string conversion.")
 
-(defconst org-html-scripts
+(defcustom org-html-scripts
   "<script type=\"text/javascript\">
 // @license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&amp;dn=gpl-3.0.txt GPL-v3-or-Later
      function CodeHighlightOn(elem, id)
@@ -255,9 +255,12 @@ property on the headline itself.")
      }
 // @license-end
 </script>"
-  "Basic JavaScript that is needed by HTML files produced by Org mode.")
+  "Basic JavaScript that is needed by HTML files produced by Org mode."
+  :group 'org-export-html
+  :package-version '(Org . "9.5")
+  :type 'string)
 
-(defconst org-html-style-default
+(defcustom org-html-style-default
   "<style type=\"text/css\">
   #content { max-width: 60em; margin: auto; }
   .title  { text-align: center;
@@ -444,7 +447,10 @@ property on the headline itself.")
   "The default style specification for exported HTML files.
 You can use `org-html-head' and `org-html-head-extra' to add to
 this style.  If you don't want to include this default style,
-customize `org-html-head-include-default-style'.")
+customize `org-html-head-include-default-style'."
+  :group 'org-export-html
+  :package-version '(Org . "9.5")
+  :type 'string)
 
 
 ;;; User Configuration Variables