Standardize spacing in explanation.txt

[benthayer]

As of this writing, we have the block of text in the explanation for intro init

The ".git" folder contains a lot of information that Git can use to help you 
manage different versions of your code. You don't ever need to do anything with
the contents of the ".git" folder directly

We manually changed the spacing, but once we implement word wrap with #274 , we will want every line of every explanation.txt to just be one long line.

Like this:

The ".git" folder contains a lot of information that Git can use to help you manage different versions of your code. You don't ever need to do anything with the contents of the ".git" folder directly