newsletter: Add mention of books

Author: jamesmunns

newsletters/2018-04-14.md

@@ -18,6 +18,7 @@ If you want to mention something in [the next newsletter], make sure to leave a
     * You can now link Embedded Rust programs [using lld]
 * [Wilfried] kicked off a blog series about [using embedded rust]
 * [Andre Richter] is writing a tutorial for using Rust to write [bare metal Raspberry Pi 3] applications
+* The Embedonomicon and the Embedded Rust Books are [now kept] in the [Embedded WG] repository, and pull requests are welcome!
 
 [Awesome Embedded Rust]: https://github.com/rust-embedded/awesome-embedded-rust
 [Embedded Rust on Stable]: https://github.com/rust-lang-nursery/embedded-wg/issues/42
@@ -28,6 +29,7 @@ If you want to mention something in [the next newsletter], make sure to leave a
 [using embedded rust]: http://ithinuel.me/embedded-rust-why/
 [Andre Richter]: https://github.com/andre-richter
 [bare metal Raspberry Pi 3]: https://github.com/andre-richter/rust-raspi3-tutorial
+[now kept]: https://github.com/rust-lang-nursery/embedded-wg/pull/78
 
 ## Embedded Projects