Update listings to account for cargo new template update

Requires rust-lang/cargo#13939.

Author: tbu-

listings/ch11-writing-automated-tests/listing-11-01/src/lib.rs

@@ -1,4 +1,4 @@
-pub fn add(left: usize, right: usize) -> usize {
+pub fn add(left: u64, right: u64) -> u64 {
     left + right
 }
 

listings/ch11-writing-automated-tests/listing-11-03/src/lib.rs

@@ -1,5 +1,5 @@
 // ANCHOR: here
-pub fn add(left: usize, right: usize) -> usize {
+pub fn add(left: u64, right: u64) -> u64 {
     left + right
 }
 

listings/ch11-writing-automated-tests/no-listing-01-changing-test-name/src/lib.rs

@@ -1,4 +1,4 @@
-pub fn add(left: usize, right: usize) -> usize {
+pub fn add(left: u64, right: u64) -> u64 {
     left + right
 }
 

listings/ch14-more-about-cargo/output-only-02-add-one/add/add_one/src/lib.rs

@@ -1,4 +1,4 @@
-pub fn add(left: usize, right: usize) -> usize {
+pub fn add(left: u64, right: u64) -> u64 {
     left + right
 }