Fix bug in Cargo.toml

Previously, the `[package.metadata.docs.rs]` section was
placed inside of the `[package]` section, effectively ending it and
making it so that the subsequent `exclude` and `build` keys were
treated as members of `[package.metadata.docs.rs]` rather than as
members of `[package]`.

Change-Id: I53a06f7885b2c29683e017bb84ace08df16350e7
diff --git a/Cargo.toml b/Cargo.toml
index dea987b..50da7b3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,9 +15,6 @@
 categories = ["cryptography"]
 repository = "https://fuchsia.googlesource.com/mundane"
 
-[package.metadata.docs.rs]
-features = ["bytes","insecure","kdf","rsa-pkcs1v15"]
-
 # Exclude these test files in order to get under the minimum crates.io crate
 # file size.
 exclude = [
@@ -28,6 +25,10 @@
 ]
 
 build = "build/main.rs"
+
+[package.metadata.docs.rs]
+features = ["bytes","insecure","kdf","rsa-pkcs1v15"]
+
 [build-dependencies]
 goblin = "0.0.24"