go/analysis/singlechecker: fix whitespace in package documentation

Consistent whitespace makes godoc render the snippet without
extraneous leading indentation.

Change-Id: If7b6910cd431ada0db0f59b7aecc9e5bd011af23
Reviewed-on: https://go-review.googlesource.com/c/tools/+/266877
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dominik Honnef <dominik@honnef.co>
diff --git a/go/analysis/singlechecker/singlechecker.go b/go/analysis/singlechecker/singlechecker.go
index 500a40a..2853077 100644
--- a/go/analysis/singlechecker/singlechecker.go
+++ b/go/analysis/singlechecker/singlechecker.go
@@ -11,7 +11,7 @@
 // all that is needed to define a standalone tool is a file,
 // example.org/findbadness/cmd/findbadness/main.go, containing:
 //
-//      // The findbadness command runs an analysis.
+// 	// The findbadness command runs an analysis.
 // 	package main
 //
 // 	import (