Add git link to the source.

ehuss · ehuss · commit 7e22f5fc1c68 · 2020-12-26T13:22:04.000-08:00
diff --git a/book.toml b/book.toml
@@ -3,3 +3,6 @@ authors = ["The Rust Project Developers"]
 multilingual = false
 src = "src"
 title = "The Edition Guide"
+
+[output.html]
+git-repository-url = "https://github.com/rust-lang/edition-guide"
