Fix variable naming in is_in_method_chain for clarity

Author: a-yossy

clippy_lints/src/dereference.rs

@@ -729,8 +729,8 @@ fn deref_method_same_type<'tcx>(result_ty: Ty<'tcx>, arg_ty: Ty<'tcx>) -> bool {
 }
 
 fn is_in_method_chain<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> bool {
-    if let ExprKind::MethodCall(_, child, _, _) = e.kind {
-        match child.kind {
+    if let ExprKind::MethodCall(_, recv, _, _) = e.kind {
+        match recv.kind {
             ExprKind::MethodCall(..)
             | ExprKind::Index(..)
             | ExprKind::Match(.., MatchSource::TryDesugar(..) | MatchSource::AwaitDesugar)