chore: update badges and remove embedded code snippet

- Update the CI Lint badge URL to include the branch name
- Update the Testing badge URL to include the branch name
- Remove the Gitter chat badge
- Add an empty line in the `main()` function
- Add an empty line in the `main()` function
- Remove the embedded code snippet from the README file

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

README.md

@@ -1,11 +1,10 @@
 # sessions
 
-[![Run CI Lint](https://github.com/gin-contrib/sessions/actions/workflows/lint.yml/badge.svg)](https://github.com/gin-contrib/sessions/actions/workflows/lint.yml)
-[![Run Testing](https://github.com/gin-contrib/sessions/actions/workflows/testing.yml/badge.svg)](https://github.com/gin-contrib/sessions/actions/workflows/testing.yml)
+[![Run CI Lint](https://github.com/gin-contrib/sessions/actions/workflows/lint.yml/badge.svg?branch=master)](https://github.com/gin-contrib/sessions/actions/workflows/lint.yml)
+[![Run Testing](https://github.com/gin-contrib/sessions/actions/workflows/testing.yml/badge.svg?branch=master)](https://github.com/gin-contrib/sessions/actions/workflows/testing.yml)
 [![codecov](https://codecov.io/gh/gin-contrib/sessions/branch/master/graph/badge.svg)](https://codecov.io/gh/gin-contrib/sessions)
 [![Go Report Card](https://goreportcard.com/badge/github.com/gin-contrib/sessions)](https://goreportcard.com/report/github.com/gin-contrib/sessions)
 [![GoDoc](https://godoc.org/github.com/gin-contrib/sessions?status.svg)](https://godoc.org/github.com/gin-contrib/sessions)
-[![Join the chat at https://gitter.im/gin-gonic/gin](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/gin-gonic/gin)
 
 Gin middleware for session management with multi-backend support:
 
@@ -251,6 +250,7 @@ func main() {
 ### MongoDB
 
 #### mgo
+
 ```go
 package main
 
@@ -291,6 +291,7 @@ func main() {
 ```
 
 #### mongo-driver
+
 ```go
 package main
 
@@ -373,7 +374,6 @@ func main() {
 
 ### GoRM
 
-[embedmd]:# (_example/gorm/main.go go)
 ```go
 package main