Disabled visited link color

The visited link color is hard to read in dark mode, and nothing else
in the gerrit UI sets the visited link color.  Set to default for
consistency.

Change-Id: I53694c4417228a462d7293afaf9b7cc6df4a8aa6
diff --git a/zuul-results-summary/zuul-results-summary.js b/zuul-results-summary/zuul-results-summary.js
index af6ca8f..c033ed0 100644
--- a/zuul-results-summary/zuul-results-summary.js
+++ b/zuul-results-summary/zuul-results-summary.js
@@ -57,7 +57,7 @@
       color: var(--primary-text-color, rgb(33, 33, 33));
     }
 
-    a:link {
+    a:link, a:visited {
       color: var(--link-color);
     }