fix brackets (<< >> instead of [[ ]])

Author: Christoph Prokop

book/C-git-commands/1-git-commands.asc

@@ -43,7 +43,7 @@ There are two ways to get a Git repository. One is to copy it from an existing r
 
 To take a directory and turn it into a new Git repository so you can start version controlling it, you can simply run `git init`.
 
-We first introduce this in [[_getting_a_repo]], where we show creating a brand new repository to start working with.
+We first introduce this in <<_getting_a_repo>>, where we show creating a brand new repository to start working with.
 
 We talk briefly about how you can change the default branch from ``master'' in <<_remote_branches>>.