gopls/internal/server: fix CSS typo

Change-Id: I391dbba608b24220f4af37f620e5f33acbad1578
Reviewed-on: https://go-review.googlesource.com/c/tools/+/593637
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
diff --git a/gopls/internal/server/assets/common.css b/gopls/internal/server/assets/common.css
index 16baa4f..3795412 100644
--- a/gopls/internal/server/assets/common.css
+++ b/gopls/internal/server/assets/common.css
@@ -73,7 +73,7 @@
 textarea.code {
   background-color: #eee;
   border: 3px;
-  border-radius: 3px
+  border-radius: 3px;
   color: black;
   overflow-x: auto;
   padding: 0.625rem;