Move the app context path example url

[gandharvas]

The Getting Started sections Optional: Set a Context Path explains how a configuration property be set in the application.yaml file but the corresponding link explaining how that configuration is accessible is missing or misplaced.

Link : https://docs.grails.org/7.0.0-M3/guide/single.html#introduction

If you want to set a context path for your application, create a configuration property in the "grails-app/conf/application.yml" file:

server:
    servlet:
        context-path: /myapp
With this configuration, the application will be available at:

Alternatively, you can also set the context path via the command line:

grails> run-app -Dgrails.server.servlet.context-path=/helloworld

http://localhost:8080/myapp/

This must have to be:
With this configuration, the application will be available at: http://localhost:8080/myapp

Issue: #967

[jamesfredley]

@gandharvas Thank you.