Avoid adding a redundant newline when printing weblistPageClosing (#665)

* Replace fmt.Println with fmt.Printf for newline-ending string.

This would otherwise be caught with the improved vet printf
checker (https://github.com/golang/go/issues/30436).

* Replace fmt.Println with fmt.Printf for newline-ending string.

This would otherwise be caught with the improved vet printf
checker (https://github.com/golang/go/issues/30436).

* Avoid adding a redundant newline when printing weblistPageClosing.
diff --git a/internal/driver/testdata/pprof.cpu.flat.addresses.weblist b/internal/driver/testdata/pprof.cpu.flat.addresses.weblist
index 2eb6b7d..d8446c8 100644
--- a/internal/driver/testdata/pprof.cpu.flat.addresses.weblist
+++ b/internal/driver/testdata/pprof.cpu.flat.addresses.weblist
@@ -99,4 +99,3 @@
 
 </body>
 </html>
-
diff --git a/internal/report/source_html.go b/internal/report/source_html.go
index 17c9f6e..851693f 100644
--- a/internal/report/source_html.go
+++ b/internal/report/source_html.go
@@ -72,5 +72,4 @@
 
 const weblistPageClosing = `
 </body>
-</html>
-`
+</html>`