move embedded struct example into godoc

Examples are nicer when they're shown in the godoc.

example_embedded_test.go

@@ -0,0 +1,41 @@
+package yaml_test
+
+import (
+	"fmt"
+	"log"
+
+        "gopkg.in/yaml.v2"
+)
+
+// An example showing how to unmarshal embedded
+// structs from YAML.
+
+type StructA struct {
+	A string `yaml:"a"`
+}
+
+type StructB struct {
+	// Embedded structs are not treated as embedded in YAML by default. To do that,
+	// add the ",inline" annotation below
+	StructA   `yaml:",inline"`
+	B string `yaml:"b"`
+}
+
+var data = `
+a: a string from struct A
+b: a string from struct B
+`
+
+func ExampleUnmarshal_embedded() {
+	var b StructB
+
+	err := yaml.Unmarshal([]byte(data), &b)
+	if err != nil {
+		log.Fatal("cannot unmarshal data: %v", err)
+	}
+        fmt.Println(b.A)
+        fmt.Println(b.B)
+        // Output:
+        // a string from struct A
+        // a string from struct B
+}

examples/embedded-structs.go

@@ -1,35 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-
-        "gopkg.in/yaml.v2"
-)
-
-type StructA struct {
-	A string `yaml:"a"`
-}
-
-type StructB struct {
-	// go-yaml will not decode embedded structs by default, to do that
-	// you need to add the ",inline" annotation below
-	StructA   `yaml:",inline"`
-	B string `yaml:"b"`
-}
-
-var data = `
-a: a string from struct A
-b: a string from struct B
-`
-
-func main() {
-	var b StructB
-
-	err := yaml.Unmarshal([]byte(data), &b)
-	if err != nil {
-                log.Fatalf("error: %v", err)
-	}
-        fmt.Println(b.A)
-        fmt.Println(b.B)
-}