Set all documentation examples to 2018 edition
diff --git a/src/expr.rs b/src/expr.rs
index d07070f..fe067cb 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -19,7 +19,7 @@
/// This type is a syntax tree enum. In Syn this and other syntax tree enums
/// are designed to be traversed using the following rebinding idiom.
///
- /// ```
+ /// ```edition2018
/// # use syn::Expr;
/// #
/// # fn example(expr: Expr) {
@@ -52,7 +52,7 @@
///
/// The pattern is similar if the input expression is borrowed:
///
- /// ```
+ /// ```edition2018
/// # use syn::Expr;
/// #
/// # fn example(expr: &Expr) {
@@ -66,7 +66,7 @@
///
/// This approach avoids repeating the variant names twice on every line.
///
- /// ```
+ /// ```edition2018
/// # use syn::{Expr, ExprMethodCall};
/// #
/// # fn example(expr: Expr) {
@@ -81,7 +81,7 @@
/// In general, the name to which a syntax tree enum variant is bound should
/// be a suitable name for the complete syntax tree enum type.
///
- /// ```
+ /// ```edition2018
/// # use syn::{Expr, ExprField};
/// #
/// # fn example(discriminant: &ExprField) {
@@ -911,7 +911,7 @@
///
/// As in:
///
- /// ```rust
+ /// ```edition2018
/// # fn f() -> bool {
/// # let n = 0;
/// match n {
@@ -2291,7 +2291,7 @@
///
/// # Example
///
- /// ```
+ /// ```edition2018
/// use syn::{braced, token, Attribute, Block, Ident, Result, Stmt, Token};
/// use syn::parse::{Parse, ParseStream};
///