Add pull request template (nilearn#2455)

* Add pull request template.

* Fix miscellaneous typos and formatting in AUTHORS.rst.

The key typos are listed below, but fixing those typos required
changing whole paragraphs to maintain line-length limits:

- Mehdi Rahim, Philippe Gervais **where payed** by the
     - I’m not sure if this should be past tense, but I kept it that
way just in case.
- A huge amount of work goes **in the scikit-learn**.

.github/pull_request_template.md

@@ -0,0 +1,24 @@
+<!---
+This is a suggested pull request template for nilearn.
+It's designed to capture information we've found to be useful in reviewing pull requests.
+
+If there is other information that would be helpful to include, please don't hesitate to add it!
+
+See here for more information on what is expected for pull requests:
+https://github.com/nilearn/nilearn/blob/master/CONTRIBUTING.rst#pull-requests
+-->
+
+<!-- Please indicate after the # which issue you're closing with this PR.
+This is helpful for the maintainers AND will magically close the issue when this
+pull request is merged!
+If the PR closes multiple issues, includes "closes" before each one is listed.
+https://help.github.com/articles/closing-issues-using-keywords -->
+Closes # .
+
+<!-- Please give a brief overview of what has changed in the PR.
+If you're not sure what to write, consider it a note to the maintainers to indicate
+what they should be looking for when they review the pull request. -->
+Changes proposed in this pull request:
+
+-
+-

AUTHORS.rst

@@ -16,7 +16,7 @@ Additional credit goes to M. Hanke and Y. Halchenko for data and packaging.
 .. _core_devs:
 
 Core developers
-.................
+...............
 
 The nilearn core developers are:
 
@@ -35,10 +35,10 @@ The nilearn core developers are:
 * Salma Bougacha https://github.com/salma1601
 
 Funding
-........
+.......
 
 Alexandre Abraham, Gael Varoquaux, Kamalakar Reddy Daddy, Loïc Estève,
-Mehdi Rahim, Philippe Gervais where payed by the `NiConnect
+Mehdi Rahim, Philippe Gervais were paid by the `NiConnect
 <https://team.inria.fr/parietal/18-2/spatial_patterns/niconnect>`_
 project, funded by the French `Investissement d'Avenir
 <http://www.gouvernement.fr/investissements-d-avenir-cgi>`_.
@@ -49,7 +49,7 @@ NiLearn is also supported by `DigiCosme <https://digicosme.lri.fr>`_
 .. _citing:
 
 Citing nilearn
-------------------------
+--------------
 
 There is no paper published yet about nilearn. We are waiting for the
 package to mature a bit. However, the patterns underlying the package
@@ -61,13 +61,14 @@ We suggest that you read and cite the paper. Thank you.
 
 
 Citing scikit-learn
-------------------------
-
-A huge amount of work goes in the scikit-learn. Researchers that invest
-their time in developing and maintaining the package deserve recognition
-with citations. In addition, the Parietal team needs the citations to the
-paper in order to justify paying a software engineer on the project. To
-guarantee the future of the toolkit, if you use it, please cite it.
+-------------------
+
+A huge amount of work goes into scikit-learn, upon which nilearn relies heavily.
+Researchers who invest their time in developing and maintaining the package
+deserve recognition with citations.
+In addition, the Parietal team needs citations to the paper in order to
+justify paying a software engineer on the project.
+To guarantee the future of the toolkit, if you use it, please cite it.
 
 See the scikit-learn documentation on `how to cite
 <http://scikit-learn.org/stable/about.html#citing-scikit-learn>`_.