Remove local version from @font-face

It's unlikely that the bundled version wouldn't load, and it's
especially unlikely that the page would load but the bundled version
would not.

Also, if it doesn't load, it should fall back to another monospace font,
which is fine.

Author: camelid

src/theme/fonts/fonts.css

@@ -96,6 +96,5 @@
   font-family: 'Source Code Pro';
   font-style: normal;
   font-weight: 500;
-  src: url('source-code-pro-v11-all-charsets-500.woff2') format('woff2'),
-       local('Source Code Pro Medium'), local('SourceCodePro-Medium');
+  src: url('source-code-pro-v11-all-charsets-500.woff2') format('woff2');
 }