Slightly modify description of Git's data storage and mention Git doc…

…umentation

Previously implied that Git only stores changes, which is incorrect, so
wanted to clarify the wording used.

Add reference to the official documentation in the introduction

git-overview.qmd

@@ -11,7 +11,7 @@ Where tracked changes can get unwieldy after multiple iterations, Git makes it e
 In addition to just being able to understand a file history, when working on a project, even if you're the only one coding, it's important to be able to go back to previous versions if you make a mistake.
 This is possible with Git!
 In fact, this book was created using Git and GitHub, so you can explore how it was put together and iterated by going to the [GitHub page]().
-Git isn't the only VCS available, but it's the most prevalent, and has a good support community, so is what will be the focus in this book.
+Git isn't the only VCS available, but it's the most prevalent, has some advantages over the alternatives in the [method of storing its data](https://git-scm.com/book/en/v2/Getting-Started-What-is-Git%3F), and has a good support community, so is what will be the focus in this book.
 
 ## What is GitHub?
 

how-git-works.qmd

@@ -17,7 +17,7 @@ This is useful for things like log files and html outputs, which are not part of
 
 So how does Git keep track of all these changes?
 It does so by creating **commits**.
-A **commit** is a snapshot of the changes in a repository at a given point in time.
+A **commit** is a snapshot of every file in a repository, along with its changes since the last snapshot, at a given point in time.
 You can think of it like saving a file in a word processor, and is an action that has to be done manually.
 We'll talk in more detail later about how to do this, but a key idea is to **commit** often, and **commit** early.
 

index.qmd

@@ -3,6 +3,7 @@
 This book accompanies the Pennsylvania State University's Center for Infectious Disease Dynamics short workshop on using Git and GitHub as researchers.
 The content will form the basis of the workshop's syllabus, and act as a reference for attendees (and others), although I would highly recommend reading through the [excellent book](https://happygitwithr.com) by Jenny Bryan and co., as well as the [GitHub docs](https://docs.github.com/en) for additional information.
 I also strongly recommend looking at the [Atlassian Git tutorials](https://www.atlassian.com/git/tutorials) for excellent in-depth tutorials about Git, and [Learn Git Branching](https://learngitbranching.js.org) for an interactive way to learn Git!
+As you become more familiar with Git, it's worth checkout out the [official Git documentation and book](https://git-scm.com/book/en/v2), which provides a wealth of information about Git and its internals.
 
 ## Motivation