Fix about_iteration koan

[#54145683]
Fix about_iteration koan

* Add curly braces to test:
  `test_each_can_use_curly_brace_blocks_too`
  on lines 42-44.

[#54145683]
Merge pull request #18 from bayendor/54145683_about_iteration_master

Fix about_iteration koan

[Delivers #54145683]