Rename examples

Ensure they show up on pub.dev

pkgs/io/example/example.dart

diff --git a/pkgs/io/example/ansi_code_example.dart b/pkgs/io/example/example.dart
similarity index 100%
rename from pkgs/io/example/ansi_code_example.dart
rename to pkgs/io/example/example.dart

pkgs/io/example/spawn_process_example.dart

diff --git a/pkgs/io/example/spawn_process.dart b/pkgs/io/example/spawn_process_example.dart
similarity index 100%
rename from pkgs/io/example/spawn_process.dart
rename to pkgs/io/example/spawn_process_example.dart