Change code style hot-key from { to `

[stevengharris]

I have been using the MarkupEditor with lots of code style elements inlined and have found the default hot-key mapping of { to be painful. To use it, you have to hit shift just to reach the {, so every toggle to inline code involves the three-key sequence of ⌘⇧{. Also after using Markdown, which just uses the ` character, it seems burdensome. I propose to change the hot key from { to `, which means using the ⌘` key sequence, and which I think will map better mentally for people used to typing Markdown.