Add t stochastic neighbour embedding to DIRECTORY.md

[Khansa435]

Describe your change:

Added my recently merged PR i.e 13476 algorithm i.e T Stochastic Neighbour embedding to DIRECTORY.md with a link to t_stochastic_neighbour_embedding.py file as well.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[Khansa435]

Hi @cclauss Please review this as it's related to our previous-merged PR.

[cclauss]

CONTRIBUTING.md describes why humans should never edit DIRECTORY.md.

• https://github.com/TheAlgorithms/Python/blob/master/CONTRIBUTING.md#other-requirements-for-submissions

Do not update the README.md or DIRECTORY.md file which will be periodically autogenerated by our GitHub Actions processes.

[Khansa435]

My bad! I noticed it wasn’t updated yet, so I assumed it needed to be done manually.