Auto merge of #675 - GuillaumeGomez:improve-ui, r=Mark-Simulacrum

Improve UI a bit

I had a hard time trying to figure out what I was reading. Thanks to `@lqd,` I was able to understand so I think a little UI improvement wouldn't necessarily be a bad idea. Here is what it looks like with this change:

![Screenshot from 2022-12-09 17-43-04](https://user-images.githubusercontent.com/3050060/206750552-c3e38cc7-7b21-4677-aa32-fad41fb2e86c.png)

It adds new "header" which provides more context to what is displayed.

assets/report.css

@@ -175,7 +175,7 @@ div.category div.crate:last-child {
     padding-bottom: 0;
 }
 
-div.category div.crate > a {
+div.category div.crate > a, div.category div.crate > span.title {
     flex: 1;
     text-decoration: none;
 }

templates/macros.html

@@ -20,6 +20,14 @@
     UTC
 {% endmacro %}
 
+{% macro crate_header() %}
+    <div class="crate">
+        <span class="title">Crate</span>
+        <span class="run">Previous run</span>
+        <span class="run">Current run</span>
+    </div>
+{% endmacro %}
+
 {% macro crate_div(crate) %}
     <div class="crate">
         <a href="{{ crate.url|safe }}" target="_blank" rel="noopener">
@@ -37,4 +45,4 @@
             </span>
         {% endfor %}
     </div>
-{% endmacro %}
+{% endmacro %}

templates/report/results.html

@@ -38,6 +38,7 @@
                         {{ name }} ({{ crates.Plain|length }})
                     </div>
                     <div class="crates hidden" id="crt-{{ name }}">
+                        {{ macros::crate_header() }}
                         {% for crate in crates.Plain %}
                             {{ macros::crate_div(crate=crate) }}
                         {% endfor %}
@@ -56,6 +57,7 @@
                                     </div>
                                 </div>
                                 <div class="crates" id="{{ name }}-tr{{ loop.index }}">
+                                    {{ macros::crate_header() }}
                                     {% for crate in subcrates %}
                                         {{ macros::crate_div(crate=crate) }}
                                     {% endfor %}
@@ -77,6 +79,7 @@
                                     </div>
                                 </div>
                                 <div class="crates" id="{{ name }}-rt{{ loop.index }}">
+                                    {{ macros::crate_header() }}
                                     {% for crate in subcrates %}
                                         {{ macros::crate_div(crate=crate) }}
                                     {% endfor %}