* Get rid of map and replace it with a multiplication of "\n" to generate document with multiple line preceding the annotation
* Reduce number from 1000 to 100 since it achieves the same goal
* Only keep one test for the multiple lines document since it's unecessary to test multiple times
* Update some language in tests names to make it clearer what we are testing
* Require the application and environnement in the notes command in order to load the config files
* Adds tests for both register_directories and register_extensions added to a config file
* It is called with `rails notes`
* It defaults to displaying [OPTIMIZE, FIXME and TODO] annotations
* It accepts custom annotations by using `rails notes -a CUSTOM_ANNOTATION OTHER_ANNOTATION`
* It defaults to look for annotations in [app config db lib test] as dictated by SourceAnnotationExtractor
* It supports ENV["SOURCE_ANNOTATION_DIRECTORIES"] but adds a deprecation warning and recommends using register_directories instead
