changed file extension from .txt to .rst

[hnhparitosh]

Due to file extension, the file was not being rendered properly.
Now, contributors can view this page properly

Description

Checklist

• Docstrings for all functions
• Gallery example in ./doc/examples (new features only)
• Benchmark in ./benchmarks, if your changes aren't covered by an
  existing benchmark
• Unit tests
• Clean style in the spirit of PEP8

For reviewers

• Check that the PR title is short, concise, and will make sense 1 year
  later.
• Check that new functions are imported in corresponding __init__.py.
• Check that new features, API changes, and deprecations are mentioned in
  doc/release/release_dev.rst.

[grlee77]

Thanks, @hnhparitosh! Two suggestions:

1.) You need to also update the line starting with .. include in doc/source/contribute.rst to point to CONTRIBUTING.rst instead of CONTRIBUTING.txt. Otherwise, this causes the online doc page for this to be empty (see the documentation that was rendered from the prior build in this PR here). Also, I don't think there is any link in the Sphinx docs to the CONTRIBUTORS file, so nothing to update there for that one.

2.) CONTRIBUTORS.txt looks like it is in Markdown format (e.g. headers marked with # instead of underscores). I would rename this one to CONTRIBUTORS.md instead.

[grlee77]

please also address this comment:

1.) You need to also update the line starting with .. include in doc/source/contribute.rst to point to CONTRIBUTING.rst instead of CONTRIBUTING.txt

[mkcor]

Dear @hnhparitosh,

Are you able to take care of the changes requested by Greg? Feel free to let us know.

Cheers,
Marianne

[mkcor]

Hi @hnhparitosh,

Can you update this PR or would you like us to take over?

[hmaarrfk]

Sorry i missed this one and merged an other PR instead :/

[mkcor]

Sorry i missed this one and merged an other PR instead :/

Oh, which one? 👀

[hmaarrfk]

https://github.com/scikit-image/scikit-image/pull/6070/files

[mkcor]

@hnhparitosh I have resolved the merge conflicts through the web interface. Unrelated, but next time please work on a dedicated feature branch to submit a contribution, as detailed in... CONTRIBUTING.rst 😉

[hmaarrfk]

./doc/release/release_0.17.rst:- Deprecate CONTRIBUTORS.txt and replace by git shortlog command (#4351)
./INSTALL.rst:    ├── CONTRIBUTORS.txt

[hmaarrfk]

Gah. I can't get the whitespace change to go away. Sorry for the many pushes.