benchstat: update AddConfig file

Change-Id: Ibe1799f47369e3b9087ee767cc5a61cfa5a8cd4d
Reviewed-on: https://go-review.googlesource.com/36029
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Kirill Smelkov <kirr@nexedi.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/benchstat/data.go b/benchstat/data.go
index 15f7acb..3c3a08b 100644
--- a/benchstat/data.go
+++ b/benchstat/data.go
@@ -157,7 +157,7 @@
 	return m
 }
 
-// AddFile adds the benchmark results in the formatted data
+// AddConfig adds the benchmark results in the formatted data
 // to the named configuration.
 func (c *Collection) AddConfig(config string, data []byte) {
 	c.Configs = append(c.Configs, config)