Standardize on syntax highlight organization and formatting

The language spec for test output lives entirely in `syntaxes/` and is specified using the `.tmLanguage` format. The pip requirements file is spread out between `syntaxes/` and `languages/` and is defined using the JSON version of the `.tmLanguages` spec. The pip requirements files should be brought in line by consolidating all of the files into `syntaxes/` and moving over to the XML format.