Add suggestion for explicit_write lint

clippy_lints/src/lib.rs

@@ -14,6 +14,7 @@
 #![feature(slice_patterns)]
 #![feature(stmt_expr_attributes)]
 #![feature(range_contains)]
+#![feature(str_escape)]
 #![allow(clippy::missing_docs_in_private_items)]
 #![recursion_limit = "256"]
 #![warn(rust_2018_idioms, trivial_casts, trivial_numeric_casts)]