Clarify the unit test summary message
Clarify the unit test summary message

Tests:
 - Make the test success message green, the test failure message red, and add appropriate prefixes to them
 - Replace the "!" with a "." in the success message. No need to get excited over some unit tests passing

[Issue](https://github.com/andypyrope/modular/issues/7)
[Project card](https://github.com/andypyrope/modular/projects/1#card-3897174)

andypyrope/modular,andypyrope/modular