Auto merge of #3950 - phansch:update_changelog, r=Manishearth
Auto merge of #3950 - phansch:update_changelog, r=Manishearth

Update changelog for Rust 1.34.0

[Rendered](https://github.com/phansch/rust-clippy/blob/update_changelog/CHANGELOG.md#rust-134-2019-04-10)

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust