Add links to the CI jobs

- active ones: Linux x86_64 and aarch64
- inactive: Windows
- none: Mac OS X

Make it more clear what 'PR' is - a Pull Request
diff --git a/docs/beginner-contribution.md b/docs/beginner-contribution.md
index 3a49862..33fb328 100644
--- a/docs/beginner-contribution.md
+++ b/docs/beginner-contribution.md
@@ -42,9 +42,9 @@
 
 If you are changing any code in Mesos, then you should build and run the tests before opening a PR. You should run `make check` and ensure that all tests pass before opening a PR.
 
-## Open a PR
+## Open a Pull Request
 
-Once changes are completed and tested, it's time to open a PR so that they can be reviewed. When your local branch is clean and ready to submit, push it to your Mesos fork. You can then open a PR against the Apache Mesos GitHub repository. Once your PR is open, you can notify the community on [Mesos Slack](/community) or on the developer mailing list.
+Once changes are completed and tested, it's time to open a Pull Request (PR) so that they can be reviewed. When your local branch is clean and ready to submit, push it to your Mesos fork. You can then open a PR against the Apache Mesos GitHub repository. Once your PR is open, you can notify the community on [Mesos Slack](/community) or on the developer mailing list.
 
 # Getting Started Guidance
 
diff --git a/docs/committing.md b/docs/committing.md
index 5a1b69c..c742d01 100644
--- a/docs/committing.md
+++ b/docs/committing.md
@@ -27,7 +27,9 @@
    this for you, but be careful when rebasing or ammending.
 4. **Never ever commit a merge**: always rebase instead, as appropriate.
    Likewise, never 'force push'.
-5. **Don't break the build**: we support Linux, Mac OS X, and Windows. However,
+5. **Don't break the build**: we support [Linux x86_64](https://ci-builds.apache.org/job/Mesos/job/Mesos-Buildbot/),
+   [Linux aarch64](https://ci-builds.apache.org/job/Mesos/job/Mesos-Buildbot-ARM/),
+   Mac OS X and [Windows](https://ci-builds.apache.org/job/Mesos/job/Mesos-Buildbot-Windows/). However,
    not all configurations are being tested in Jenkins, so be aware of that.
    Also, pay attention to the Jenkins review bot if it flags a review as
    breaking the build. Note that if you do break the build, the fixes are