Convert output of {{ buyer_first_name }} to title case by default

Most of our customers order on their mobile phone, which often leads to names written like james bond, JAMES BOND, jameS bond, etc.

Now, when I use the first name in an email template, the name is pulled in from WooCommerce as-is, resulting in salutations like 'Dear james', 'Dear JAMES', 'Dear jameS', etc. which makes it quite obvious that this is an automated message.

Therefore, in order to keep up the appearance that request (and thank you) emails are personal messages, I'd suggest formatting the first name internally to Title Case before displaying it through the { buyer_first_name }} variable.

This tweak should result in the first name being displayed correctly most of the time (there are probably edge cases, but I can't think of any at the moment).