doc: ensure changelog uses %Y-%m-%d format, not %Y-%d-%m

docs/documentation/changelog.md

@@ -8,7 +8,7 @@ nav: ../
# History of Changes
{% comment %}There are no new lines after "for" and after "endfor" below in order to keep formatting of the output list sane.{% endcomment %}
* [Introduction and explanation of symbols](#introduction)
{% for post in site.categories.new_release %}* [Version {{ post.version }} ({{ post.date | date: "%Y-%d-%m"}})](#version_{{ post.version }})
{% for post in site.categories.new_release %}* [Version {{ post.version }} ({{ post.date | date: "%Y-%m-%d"}})](#version_{{ post.version }})
	* [Contributors to this release](#contributors_{{ post.version }})
{% endfor %}* [Version 9.4.1212 (2016-11-01)](#version_9.4.1212)
	* [Contributors to this release](#contributors_9.4.1212)
@@ -77,7 +77,7 @@ denote the various action types:![add](../media/img/add.jpg)=add,

{% for post in site.categories.new_release %}
<a name="version_{{ post.version }}"></a>
## Version {{ post.version }} ({{ post.date | date: "%Y-%d-%m"}})
## Version {{ post.version }} ({{ post.date | date: "%Y-%m-%d"}})
{{ post.content }}
{% endfor %}