Clippy fixes for new Rust version (#3392)

crates/nu-data/src/config/nuconfig.rs

@@ -59,8 +59,8 @@ impl NuConfig {
         };
 
         Ok(NuConfig {
-            file_path,
             vars,
+            file_path,
             modified_at,
         })
     }

crates/nu-data/src/utils/internal.rs

@@ -16,19 +16,11 @@ pub struct Labels {
 
 impl Labels {
     pub fn at(&self, idx: usize) -> Option<&str> {
-        if let Some(k) = self.x.get(idx) {
-            Some(&k[..])
-        } else {
-            None
-        }
+        self.x.get(idx).map(|k| &k[..])
     }
 
     pub fn at_split(&self, idx: usize) -> Option<&str> {
-        if let Some(k) = self.y.get(idx) {
-            Some(&k[..])
-        } else {
-            None
-        }
+        self.y.get(idx).map(|k| &k[..])
     }
 
     pub fn grouped(&self) -> impl Iterator<Item = &String> {