Don't wrap prev/next text on diff view

This change prevents the wrapping of prev/next text in the diff view so
that the links are placed consistently on each page.

Bug: Issue 5195
Change-Id: Ic5a2c896858c00e43b8506b227c80458a3b85aed
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
index e57940a..3e1b415 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
@@ -51,6 +51,9 @@
       .downloadLink:not([href]) {
         color: #999;
       }
+      .navLinks {
+        white-space: nowrap;
+      }
       .reviewed {
         display: inline-block;
         margin: 0 .25em;