fix example (le sigh)

Author: nikomatsakis

src/test/ui/async-await/return-ty-unsize-coercion.rs

@@ -33,11 +33,11 @@ fn unsize_slice_coercion() {
 
 // Unsizing coercion from `&[&str; 1]` to `&[&str]`
 fn unsize_slice_str_coercion() {
-    fn func() -> &'static [&'static str] {
+    fn sync_example() -> &'static [&'static str] {
         &["hi"]
     }
 
-    async fn func() -> &'static [&'static str] {
+    async fn async_example() -> &'static [&'static str] {
         &["hi"]
     }
 }