fix(helm): fix doc string for ErrNotList

This just moves a var declaration to the top of a file and then properly
documents it.

cmd/helm/strvals/parser.go

@@ -26,6 +26,9 @@ import (
 	"github.com/ghodss/yaml"
 )
 
+// ErrNotList indicates that a non-list was treated as a list.
+var ErrNotList = errors.New("not a list")
+
 // ToYAML takes a string of arguments and converts to a YAML document.
 func ToYAML(s string) (string, error) {
 	m, err := Parse(s)
@@ -156,8 +159,6 @@ func (t *parser) val() ([]rune, error) {
 	return v, err
 }
 
-var ErrNotList = errors.New("not a list")
-
 func (t *parser) valList() ([]interface{}, error) {
 
 	r, _, e := t.sc.ReadRune()