Auto merge of #3820 - mikerite:remove-feature-try-from, r=Manishearth

Remove `#[feature(try_from)]`

`try_from` is now stable.

Author: bors

clippy_lints/src/lib.rs

@@ -9,7 +9,6 @@
 #![recursion_limit = "256"]
 #![warn(rust_2018_idioms, trivial_casts, trivial_numeric_casts)]
 #![feature(crate_visibility_modifier)]
-#![feature(try_from)]
 
 // FIXME: switch to something more ergonomic here, once available.
 // (currently there is no way to opt into sysroot crates w/o `extern crate`)

src/driver.rs

@@ -1,7 +1,6 @@
 // error-pattern:yummy
 #![feature(box_syntax)]
 #![feature(rustc_private)]
-#![feature(try_from)]
 #![allow(clippy::missing_docs_in_private_items)]
 
 // FIXME: switch to something more ergonomic here, once available.