collect now triggers E0283 instad of E0282

Author: estebank

compiler/rustc_error_codes/src/error_codes/E0282.md

@@ -3,7 +3,7 @@ The compiler could not infer a type and asked for a type annotation.
 Erroneous code example:
 
 ```compile_fail,E0282
-let x = "hello".chars().rev().collect();
+let x = None;
 ```
 
 This error indicates that type inference did not result in one unique possible

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -182,7 +182,7 @@ fn closure_args(fn_sig: &ty::PolyFnSig<'_>) -> String {
 
 pub enum TypeAnnotationNeeded {
     /// ```compile_fail,E0282
-    /// let x = "hello".chars().rev().collect();
+    /// let _ = None;
     /// ```
     E0282,
     /// An implementation cannot be chosen unambiguously because of lack of information.