spanner: fix typo in doc.go
@@ -192,7 +192,7 @@ For Cloud Spanner columns that may contain NULL, use one of the NullXXX types,
like NullString:
var ns spanner.NullString
- if err =: row.Column(0, &ns); err != nil {
+ if err := row.Column(0, &ns); err != nil {
// TODO: Handle error.
}
if ns.Valid {
