Fixed added padding around hr tags in details blocks

Due to manual handling & wrapping of non-block content in details block
not taking hr elements into account.
For #3963

resources/js/wysiwyg/config.js

@@ -268,7 +268,7 @@ export function build(options) {
             '-doc-root[doc-root|#text]',
             '-li[details]',
             '+code-block[pre]',
-            '+doc-root[p|h1|h2|h3|h4|h5|h6|blockquote|code-block|div]',
+            '+doc-root[p|h1|h2|h3|h4|h5|h6|blockquote|code-block|div|hr]',
         ].join(','),
         plugins: gatherPlugins(options),
         contextmenu: false,

resources/js/wysiwyg/util.js

@@ -14,4 +14,5 @@ export const blockElementTypes = [
     'ul',
     'ol',
     'table',
+    'hr',
 ];