Update package doc.

module.go

@@ -1,15 +1,12 @@
 // Package module provides a way to do dependency injection, with type-safe, without performance penalty.
-// See examples for the basic usage.
+// See [examples_test.go](./examples_test.go) for the basic usage.
 package module
 
 import (
 	"context"
 	"reflect"
 )
 
-// BuildFunc is the constructor of an Instance.
-type BuildFunc[T any] func(context.Context) (T, error)
-
 type moduleKey string
 
 // Module provides a module to inject and retreive an instance with its type.

provider.go

@@ -8,21 +8,24 @@ type Provider interface {
 	value(ctx context.Context) (any, error)
 }
 
+// BuildFunc is the constructor of an Instance.
+type BuildFunc[T any] func(context.Context) (T, error)
+
 type funcProvider[T any] struct {
 	moduleKey moduleKey
 	ctor      BuildFunc[T]
 }
 
 // ProvideWithFunc returns a provider which provides instances creating from `ctor` function.
-func (m *Module[T]) ProvideWithFunc(ctor BuildFunc[T]) Provider {
+func (m Module[T]) ProvideWithFunc(ctor BuildFunc[T]) Provider {
 	return &funcProvider[T]{
 		moduleKey: m.moduleKey,
 		ctor:      ctor,
 	}
 }
 
 // ProvideValue returns a provider which always provides given `value` as instances.
-func (m *Module[T]) ProvideValue(value T) Provider {
+func (m Module[T]) ProvideValue(value T) Provider {
 	return m.ProvideWithFunc(func(context.Context) (T, error) {
 		return value, nil
 	})