[doc] Reorganize the changelog and the way it's displayed in the documentation

Author: Pierre-Sassoulas

.github/PULL_REQUEST_TEMPLATE.md

@@ -3,12 +3,11 @@ Thank you for submitting a PR to pylint!
 
 To ease the process of reviewing your PR, do make sure to complete the following boxes.
 
-- [ ] Add a ChangeLog entry describing what your PR does.
-- [ ] If it's a new feature, or an important bug fix, add a What's New entry in
-      `doc/whatsnew/<current release.rst>`.
 - [ ] Write a good description on what the PR does.
+- [ ] If it's a new feature, or an important bug fix, add a What's New entry in
+      ``doc/whatsnew/2/2.14/summary.rst`` otherwise in ``doc/whatsnew/2/2.14/full.rst``.
 - [ ] If you used multiple emails or multiple names when contributing, add your mails
-   and preferred name in ``script/.contributors_aliases.json``
+      and preferred name in ``script/.contributors_aliases.json``
 -->
 
 ## Type of Changes
@@ -24,9 +23,10 @@ To ease the process of reviewing your PR, do make sure to complete the following
 
 ## Description
 
-<!--
-If this PR fixes a particular issue, use the following to automatically close that issue
-once this PR gets merged:
--->
+<!-- If this PR reference an issue without fixing it: -->
+
+Refs #XXXX
+
+<!-- If this PR fixes an issue, use the following to automatically close when we merge: -->
 
-Closes #XXX
+Closes #XXXX