reactions: Change color of reaction counter from blue to black.

The blue font color on the vote_text beside the reactions in
light mode made it seem like a link which it's not, so it has
been changed to regular font color.

We preserve the blue font color on hover, matching the add-reaction
button.

static/styles/reactions.css

@@ -53,12 +53,15 @@
         top: 1px;
         font-size: 90%;
         display: flex;
-        color: hsl(200, 100%, 40%);
         margin: 0 3px;
         padding: 2px 0;
         line-height: 1em;
     }
 
+    .message_reaction:hover .message_reaction_count {
+        color: hsl(200, 100%, 40%);
+    }
+
     i {
         font-size: 1.3em;
         float: left;