Code highlight and photo-swipe can be disabled for post listing page

[bkoprucu]

https://github.com/jeffreytse/jekyll-theme-yat/blob/main/_includes/head.html#L17-L18

Disabling the following for post listing page for improved performance:

  {%- include extensions/code-highlight.html -%}
  {%- include extensions/photo-swipe.html -%}

Can be wrapped in something like:

  {%- unless page.name == 'index.html' or page.name == 'posts.html' -%}
    {%- include extensions/code-highlight.html -%}
    {%- include extensions/photo-swipe.html -%}
  {%- endunless %}