Fix warnings about deprecated items

Author: phimuemue

examples/iris.rs

@@ -55,7 +55,7 @@ fn main() {
     // using Itertools::fold_results to create the result of parsing
     let irises = DATA.lines()
                      .map(str::parse)
-                     .fold_results(Vec::new(), |mut v, iris: Iris| {
+                     .fold_ok(Vec::new(), |mut v, iris: Iris| {
                          v.push(iris);
                          v
                      });

src/lib.rs

@@ -89,7 +89,6 @@ pub mod structs {
         Batching,
         MapInto,
         MapOk,
-        MapResults,
         Merge,
         MergeBy,
         TakeWhileRef,
@@ -100,7 +99,7 @@ pub mod structs {
         Update,
     };
     #[allow(deprecated)]
-    pub use crate::adaptors::Step;
+    pub use crate::adaptors::{MapResults, Step};
     #[cfg(feature = "use_std")]
     pub use crate::adaptors::MultiProduct;
     #[cfg(feature = "use_std")]