Horizontal section on overview page for link to Try Git

[cobyism]

This implements the changes discussed in #80—i.e. removing the Try Git callout from the hero block and giving it a full-width horizontal section for it further down on the page. It’s been added as a partial too, in case we ever want to include it elsewhere on the site :grinning:

:zap: Props to @dandenney for proposing the change!

Here’s what it looks like:

It also collapses down where possible on smaller viewports. An example:

Any more suggestions or concerns before this gets merged?

/cc @github/training-team @Gregg

[matthewmccullough]

@github/training-team are you good with this change?

[jroll]

:+1:

[brntbeer]

I'm a fan! This looks good

[tlberglund]

I am :100:% fine with honoring Try Git in this way. Mergifying.