feat: add hx- prefix to Hextra Tailwind CSS classes (#300)

* feat: add prefix to tailwind css classes

* fix: remove unnecessary prefixes

* fix: add missing prefix in other places

* chore: regenerate hugo_stats.json

* chore: run `npm run build:css`

* chore: add `hx-` prefix to _index.fa.md

* fix: lang switcher display issue

* fix: add `hx-` prefix to showcase/index.fa.md

* fix: lang switch param mistake

exampleSite/content/showcase/index.fa.md

@@ -5,9 +5,9 @@ toc: false
 layout: wide
 ---
 
-<div class="mt-4"></div>
+<div class="hx-mt-4"></div>
 
-<p class="mb-12 text-center text-lg text-gray-500 dark:text-gray-400">
+<p class="hx-mb-12 hx-text-center hx-text-lg hx-text-gray-500 dark:hx-text-gray-400">
 پروژه‌های متن‌باز که توسط هگزترا طراحی شده‌اند.
 </p>