_includes/sharing.html

{%- if site.sharing.provider == 'addtoany' -%}
  {%- include sharing-providers/addtoany.html -%}
{%- elsif site.sharing.provider == 'addthis' -%}
  {%- include sharing-providers/addthis.html -%}
  {%- elsif site.sharing.provider == 'custom' -%}
  {%- include sharing-providers/custom.html -%}
{%- endif -%}