Fix clippy lints (#2651)

crates/nu-cli/tests/commands/into_int.rs

@@ -9,7 +9,7 @@ fn into_int_filesize() {
         "#
     ));
 
-    assert!(actual.out.contains("1"));
+    assert!(actual.out.contains('1'));
 }
 
 #[test]
@@ -21,5 +21,5 @@ fn into_int_int() {
         "#
     ));
 
-    assert!(actual.out.contains("1"));
+    assert!(actual.out.contains('1'));
 }

crates/nu-cli/tests/commands/keep/mod.rs

@@ -1,3 +1,3 @@
-mod keep;
+mod rows;
 mod until;
 mod while_;

crates/nu-cli/tests/commands/random/integer.rs

@@ -33,5 +33,5 @@ fn generates_0() {
         "#
     ));
 
-    assert!(actual.out.contains("0"));
+    assert!(actual.out.contains('0'));
 }