Minor paragraph edit from code modification.

Parts of the paragraph referencing lines from code changed.

book/B-embedding-git/sections/libgit2.asc

@@ -45,7 +45,8 @@ int main()
 }
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-The first couple of lines open a Git repository.
+The first line in the main function initializes the global state for using libgit2 library functions.
+The next couple of lines open a Git repository.
 The `git_repository` type represents a handle to a repository with a cache in memory.
 This is the simplest method, for when you know the exact path to a repository's working directory or `.git` folder.
 There's also the `git_repository_open_ext` which includes options for searching, `git_clone` and friends for making a local clone of a remote repository, and `git_repository_init` for creating an entirely new repository.