Code optimized (#523)

* optimized markdown generator

* optimized markdown generator

* optimized markdown generator

* add more comment

* add comment

* add comment

* add comments for rpc tool

* add comments for model tool

* add comments for model tool

* add comments for model tool

* add comments for config tool

* add comments for config tool

* add comments

* add comments

* add comments

* add comments

* add comment

* remove rpc main head info

* add comment

* optimized

Co-authored-by: anqiansong <anqiansong@xiaoheiban.cn>

tools/goctl/rpc/generator/defaultgenerator.go

@@ -6,18 +6,22 @@ import (
 	"github.com/tal-tech/go-zero/tools/goctl/util/console"
 )
 
-type defaultGenerator struct {
+// DefaultGenerator defines the environment needs of rpc service generation
+type DefaultGenerator struct {
 	log console.Console
 }
 
-func NewDefaultGenerator() *defaultGenerator {
+// NewDefaultGenerator returns an instance of DefaultGenerator
+func NewDefaultGenerator() *DefaultGenerator {
 	log := console.NewColorConsole()
-	return &defaultGenerator{
+	return &DefaultGenerator{
 		log: log,
 	}
 }
 
-func (g *defaultGenerator) Prepare() error {
+// Prepare provides environment detection generated by rpc service,
+// including go environment, protoc, whether protoc-gen-go is installed or not
+func (g *DefaultGenerator) Prepare() error {
 	_, err := exec.LookPath("go")
 	if err != nil {
 		return err