Added version note about wildcard variables language feature of Dart …

…3.7 (#6432)

Co-authored-by: Marya <111139605+MaryaBelanger@users.noreply.github.com>

src/content/effective-dart/style.md

@@ -301,6 +301,18 @@ In contrast, top-level functions and method declarations don't have that context
 so their parameters must be named so that it's clear what each parameter is for,
 even if it isn't used.
 
+:::version-note
+Since Dart 3.7, the [wildcard variable `_`][] no longer creates a variable, so you can
+use `_` for multiple parameters simultaneously without name collision:
+
+```dart tag=good
+(_, _) {
+  print('error');
+}
+```
+:::
+
+[wildcard variable `_`]: /language/variables#wildcard-variables
 
 ### DON'T use a leading underscore for identifiers that aren't private