feat: social media metadata (title, preview image, etc.) #367

Author: echasnovski

_layouts/default.html

@@ -5,6 +5,13 @@
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <meta name="description" content="{{site.description}}">
+    <meta property="og:description" content="Hyperextensible Vim-based text editor">
+    <meta property="og:image" content="https://raw.githubusercontent.com/neovim/neovim.github.io/master/logos/neovim-logo-social-preview.png">
+    <meta property="og:image:alt" content="Robot Marvim pointing at Neovim logo">
+    <meta property="og:site_name" content="Neovim">
+    <meta property="og:title" content="Neovim">
+    <meta property="og:type" content="website">
+    <meta property="og:url" content="https://neovim.io/index.html">
     {% feed_meta %}
     <title>{% if page.title %}{{ page.title }} - {% endif %}{{ site.title }}</title>