feat: better demo site (#1241)

* demo: add image-gallery post

* demo: change language weight

* demo: add multilanguage about page

* demo: change title and url

* demo: add shortcode documentation with multi-language support

* demo: improve markdown guide post

* demo: improve Math Typesetting post

* demo: rename Markdown Syntax Guide post

* demo: remove emoji support post

* demo: remove placeholder text post

* demo: remove rich-content post

* demo: rename image gallery page bundle

* demo: add multilingual `Documentation` category

* demo: Increase pagination pager size from 3 to 5.

* demo: add multilingual links, search, and archives pages

* demo: remove `ar` from demosite

demo/config/_default/hugo.toml

@@ -1,7 +1,6 @@
-baseURL      = "https://example.com/"
+baseURL      = "https://demo.stack.jimmycai.com/"
 languageCode = "en-us"
-title        = "Example Site"
-copyright    = "Example Person"
+title        = "Hugo Theme Stack"
 
 # Theme i18n support
 # See i18n folder for available languages
@@ -12,10 +11,10 @@ defaultContentLanguage = "en"
 hasCJKLanguage = false
 
 [[module.imports]]
-path = "github.com/CaiJimmy/hugo-theme-stack/v3"
+    path = "github.com/CaiJimmy/hugo-theme-stack/v3"
 
 [pagination]
-    pagerSize = 3
+    pagerSize = 5
 
 [permalinks]
     post = "/p/:slug/"