Update CHANGELOG template to put issue number in the start of the line

This makes using multiple paragraphs per entry possible

changelog/_template.rst

@@ -13,8 +13,7 @@
 
 {% if definitions[category]['showcontent'] %}
 {% for text, values in sections[section][category]|dictsort(by='value') %}
-- {{ text }}{% if category != 'vendor' %} (`{{ values[0] }} <https://github.com/pytest-dev/pytest-xdist/issues/{{ values[0][1:] }}>`_){% endif %}
-
+- `{{ values[0] }} <https://github.com/pytest-dev/pytest-xdist/issues/{{ values[0][1:] }}>`_: {{ text }}
 
 {% endfor %}
 {% else %}