flutter: add create example (#9200)

pages/common/flutter.md

@@ -3,9 +3,9 @@
 > Google's free, open source, and cross-platform mobile app SDK.
 > More information: <https://github.com/flutter/flutter/wiki/The-flutter-tool>.
 
-- Display help about a specific command:
+- Initialize a new Flutter project in a directory of the same name:
 
-`flutter help {{command}}`
+`flutter create {{project_name}}`
 
 - Check if all external tools are correctly installed:
 
@@ -30,3 +30,7 @@
 - Build a release APK targeting most modern smartphones:
 
 `flutter build apk --target-platform {{android-arm}},{{android-arm64}}`
+
+- Display help about a specific command:
+
+`flutter help {{command}}`