Snippet examples don't get registered when used with angle brackets

[abel-n]

ember-code-snippet's appropriate snippetRegexes options that is set up in this addon's ember-cli-build.js can't handle angle brackets, which might be misleading: although the docs do mention that:

you can copy-paste this block to get going in your own app

but they don't mention that actually any other way of invoking it, like naming <DocsDemo> yield something other than demo, using angle brackets or having example code in the same line as <demo.example> opening tag will provide with erroneous / unintended behavior.

I'll submit a PR to address angle bracket invocation but maybe one line in the <DocsDemo> docs could mention that users should always use demo as the yielded hash's reference.

[RobbieTheWagner]

@abel-n there is a PR for it already #342

It has been waiting on tests. Would you be able to help with tests perhaps?

[abel-n]

@rwwagner90 I don't know how to push to that PR but I opened another one. I wasn't sure what exactly to test but I think most of the stuff is covered.