When suggesting to borrow, remove useless clones

src/test/ui/issues/issue-61106.rs

@@ -0,0 +1,6 @@
+fn main() {
+    let x = String::new();
+    foo(x.clone()); //~ ERROR mismatched types
+}
+
+fn foo(_: &str) {}

src/test/ui/issues/issue-61106.stderr

@@ -0,0 +1,15 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-61106.rs:3:9
+   |
+LL |     foo(x.clone());
+   |         ^^^^^^^^^
+   |         |
+   |         expected &str, found struct `std::string::String`
+   |         help: consider borrowing here: `&x`
+   |
+   = note: expected type `&str`
+              found type `std::string::String`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.