Update links to doc files

[emmanuel-ferdman]

What does this PR do?

PR #2291 moved the different docs files to different location. This PR adjusts the sources.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue? Please add a link
  to it if that's the case.
• Did you write any new necessary tests?
• If this adds a new model, can you run a few training steps on TPU in Colab to ensure that no XLA incompatible OP are used?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[emmanuel-ferdman]

@grasskin @divyashreepathihalli kind reminder.