internal/lsp: fix unnecessary error logging

In internal/lsp/link.go appeared a bug that error message is printed
even if error is not apeared. this commit is fixing this behaviour.

Fixes golang/go#33087

Change-Id: I932546867d78c5c0c3d2c9dabd13287f6837f458
Reviewed-on: https://go-review.googlesource.com/c/tools/+/186037
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
diff --git a/internal/lsp/link.go b/internal/lsp/link.go
index 734d3eb..96c8470 100644
--- a/internal/lsp/link.go
+++ b/internal/lsp/link.go
@@ -42,7 +42,10 @@
 			}
 			target = "https://godoc.org/" + target
 			l, err := toProtocolLink(view, m, target, n.Pos(), n.End())
-			view.Session().Logger().Errorf(ctx, "cannot initialize DocumentLink %s: %v", n.Path.Value, err)
+			if err != nil {
+				view.Session().Logger().Errorf(ctx, "cannot initialize DocumentLink %s: %v", n.Path.Value, err)
+				return false
+			}
 			links = append(links, l)
 			return false
 		case *ast.BasicLit: