Change the syntax of the ‘code-block’ Markdown Mode snippet

This syntax works with the ‘Markdown Here’ plugin for Thunderbird,
while the tilde-version does not.
Typo Mode: Move hooks to right places for Markdown and Org Mode

Setting the hooks when loading Typo Mode was not having the intended
effect since Emacs may not load the other modes until after it loads
Typo Mode.
Load Typo Mode when using Text Mode
Tweak the Markdown snippet for code blocks
Add a snippet for my blog titles in Markdown documents