Improve CONTRIBUTING.md

CONTRIBUTING.md

@@ -6,12 +6,12 @@ Before doing so, here are a few guidelines:
   [license](https://github.com/Kinto/kinto/blob/master/LICENSE).
 * Use pull-requests early so it's open for discussion, even if your
   contribution isn't ready yet.
-* All pull requests should include tests, they help us avoiding regressions in
+* All pull requests should include tests, as they help us avoid regressions in
   our code.
 * A pull-request adding functionality should also update the documentation
   accordingly.
-* [TravisCI integration tests](https://travis-ci.org/Kinto/kinto) should be
+* [Travis CI integration tests](https://travis-ci.org/Kinto/kinto) should be
   green.
 * If you're interested, you can also check the [contributing
   documentation](https://kinto.readthedocs.io/en/latest/community.html#how-to-contribute)
-  which goes into more details.
+  guide which goes into more details.