Support parsing TSX code

[mylinhdao]

Support parsing TSX code with tests

Closes #9

Description

• Added tests to support TSX parser.

• For TSX and TypeScript files, type declaration are counted for classes-metric if they have an implementation. Type alias will not be counted. E.g: Expressions like type name = any are not counted, but type name = {firstname: string, lastname: string} will be counted.

  Definition of Done

  A PR is only ready for merge once all the following acceptance criteria are fulfilled:

• [x] All TODOs related to this PR have been closed

• [x] There are automated tests for newly written code and bug fixes

• [x] All bugs discovered while working on this PR have been submitted as issues (if not already an open issue)

• [x] Documentation (README.md, UPDATE_GRAMMARS.md) has been updated

[ce-bo]

Would you please add a short description what this PR is changing? I think multiple things are done here, not only adding tests if I am not mistaken, right?

[mylinhdao]

@ce-bo yes, you are right. I have added the description.