Do not lighten blockquote font color

It is confusing to have blockquote content displayed with a lighter
font color. Usually, quotes are important to the text while reducing
the contrast may hint a user it is not. In my case, I usually skip the
content of the blockquote as it was some additional note in the text.

Without the color change, the blockquote is still indented
differently, with the vertical bar. It should be enough for a user to
identify it as a quote.

ui/static/css/common.css

@@ -824,7 +824,6 @@ article.feed-parsing-error {
     margin-left: 20px;
     margin-top: 20px;
     margin-bottom: 20px;
-    color: #888;
     line-height: 1.4em;
     font-family: var(--entry-content-quote-font-family);
 }