static/shared/tabnav: ran prettier

Change-Id: I154d4d35007a59dac4167686348f5d1a6de1f5f6
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/347402
Trust: Jamal Carvalho <jamal@golang.org>
Run-TryBot: Jamal Carvalho <jamal@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/static/shared/tabnav/tabnav.md b/static/shared/tabnav/tabnav.md
index 1f51430..fa42c72 100644
--- a/static/shared/tabnav/tabnav.md
+++ b/static/shared/tabnav/tabnav.md
@@ -10,4 +10,4 @@
   </ul>
   <hr />
 </nav>
-```
\ No newline at end of file
+```