Avoid overriding the entire index.hbs file

Avoids breakage across mdBook versions (e.g. live-reload recently stopped working)

Author: ISSOtm

book.toml

@@ -41,7 +41,7 @@ traverse-parent-directories = false
 optional = true
 exclude = [
 	'https://github\.com/gbdev/pandocs/tree/', # Do not check the "this was generated from commit N" link, as the commit may not have been pushed yet
-  'print.html', # Do not check the print page, as it is generated separately
-  'single.html', # Do not check the single page, as it is generated separately
-  'http[s]*://problemkaputt\.de', # Skip checking problemkaputt.de, as connection to this domain is generally unreliable
+	'print.html', # Do not check the print page, as it is generated separately
+	'single.html', # Do not check the single page, as it is generated separately
+	'http[s]*://problemkaputt\.de', # Skip checking problemkaputt.de, as connection to this domain is generally unreliable
 ]

theme/head.hbs

@@ -0,0 +1,9 @@
+<!-- Open Graph tags-->
+<meta name="og:site_name" content="summary" />
+<meta name="og:image" content="https://gbdev.io/pandocs/favicon.png" />
+<meta name="og:title" content="{{ title }}" />
+<meta name="og:description" content="{{ description }}" />
+
+<!-- Twitter meta tags -->
+<meta name="twitter:card" content="summary" />
+<meta name="twitter:site" content="@gbdev0" />