Remove superflous whitespace from PR template

It keeps driving me nuts.

.github/pull_request_template.md

@@ -1,24 +1,24 @@
-Following this checklist to help us incorporate your 
+Following this checklist to help us incorporate your
 contribution quickly and easily:
 
- - [ ] Make sure there is a [JIRA issue](https://issues.apache.org/jira/browse/MJAVADOC) filed 
-       for the change (usually before you start working on it).  Trivial changes like typos do not 
-       require a JIRA issue.  Your pull request should address just this issue, without 
+ - [ ] Make sure there is a [JIRA issue](https://issues.apache.org/jira/browse/MJAVADOC) filed
+       for the change (usually before you start working on it).  Trivial changes like typos do not
+       require a JIRA issue.  Your pull request should address just this issue, without
        pulling in other changes.
  - [ ] Each commit in the pull request should have a meaningful subject line and body.
  - [ ] Format the pull request title like `[MJAVADOC-XXX] - Fixes bug in ApproximateQuantiles`,
        where you replace `MJAVADOC-XXX` with the appropriate JIRA issue. Best practice
-       is to use the JIRA issue title in the pull request title and in the first line of the 
+       is to use the JIRA issue title in the pull request title and in the first line of the
        commit message.
  - [ ] Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
- - [ ] Run `mvn clean verify -Prun-its` to make sure basic checks pass. A more thorough check will 
+ - [ ] Run `mvn clean verify -Prun-its` to make sure basic checks pass. A more thorough check will
        be performed on your pull request automatically.
 
 If your pull request is about ~20 lines of code you don't need to sign an
 [Individual Contributor License Agreement](https://www.apache.org/licenses/icla.pdf) if you are unsure
 please ask on the developers list.
 
-To make clear that you license your contribution under 
+To make clear that you license your contribution under
 the [Apache License Version 2.0, January 2004](http://www.apache.org/licenses/LICENSE-2.0)
 you have to acknowledge this by using the following check-box.