Clean up violations of Dart lint "avoid_single_cascade_in_expression_statements".
AVOID single cascade in expression statements.

[Lint documentation](https://dart-lang.github.io/linter/lints/avoid_single_cascade_in_expression_statements)
[Dart lints discussion](http://g/dart-lints/Pn95rk2Uj28/HTz34tc9BgAJ)

More information: http://go/dart-trivial-lint-cleanup-lsc

Tested:
    tap_presubmit: http://test/OCL:354475262:BASE:354467909:1611926611261:809355d6
    Sample tests for this CL passed, but some tests failed during the TGP run. Test failures are believed to be unrelated to this CL
PiperOrigin-RevId: 354902189
diff --git a/lib/src/async/web_element.dart b/lib/src/async/web_element.dart
index 7eb1211..2e2b5eb 100644
--- a/lib/src/async/web_element.dart
+++ b/lib/src/async/web_element.dart
@@ -165,9 +165,9 @@
     var out = StringBuffer()..write(context);
     if (locator is By) {
       if (index == null) {
-        out..write('.findElement(');
+        out.write('.findElement(');
       } else {
-        out..write('.findElements(');
+        out.write('.findElements(');
       }
       out..write(locator)..write(')');
     } else {