Revert conversion of documentation to .adoc (#7533)

* Revert "Move `MAINTAINERS` to the root folder (#7528)"

This reverts commit 43e4efba.

* Revert "Convert `README` and `CONTRIBUTING` from Markdown to AsciiDoc (#7527)"

This reverts commit 48edf2c6.

README.adoc → README.md

-+++
 <a href="https://jenkins.io">
   <picture>
     <source width="400" media="(prefers-color-scheme: dark)" srcset="https://www.jenkins.io/images/jenkins-logo-title-dark.svg">
     <img width="400" src="https://www.jenkins.io/images/jenkins-logo-title.svg">
   </picture>
 </a>
-+++
 
-== About
+# About
 
-https://www.jenkins.io/changelog[image:https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog%2Fbadge.json[Jenkins Regular Release]]
-https://www.jenkins.io/changelog-stable[image:https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog-stable%2Fbadge.json[Jenkins LTS Release]]
-https://hub.docker.com/r/jenkins/jenkins/[image:https://img.shields.io/docker/pulls/jenkins/jenkins.svg[Docker Pulls]]
-https://bestpractices.coreinfrastructure.org/projects/3538[image:https://bestpractices.coreinfrastructure.org/projects/3538/badge[CII Best Practices]]
+[![Jenkins Regular Release](https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog%2Fbadge.json)](https://www.jenkins.io/changelog)
+[![Jenkins LTS Release](https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog-stable%2Fbadge.json)](https://www.jenkins.io/changelog-stable)
+[![Docker Pulls](https://img.shields.io/docker/pulls/jenkins/jenkins.svg)](https://hub.docker.com/r/jenkins/jenkins/)
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/3538/badge)](https://bestpractices.coreinfrastructure.org/projects/3538)
 
 In a nutshell, Jenkins is the leading open-source automation server.
-Built with Java, it provides over 1,800 https://plugins.jenkins.io/[plugins] to support automating virtually anything,
+Built with Java, it provides over 1,800 [plugins](https://plugins.jenkins.io/) to support automating virtually anything,
 so that humans can spend their time doing things machines cannot.
 
-== What to Use Jenkins for and When to Use It
+# What to Use Jenkins for and When to Use It
 
 Use Jenkins to automate your development workflow, so you can focus on work that matters most. Jenkins is commonly used for:
 
-* Building projects
-* Running tests to detect bugs and other issues as soon as they are
-introduced
-* Static code analysis
-* Deployment
+- Building projects
+- Running tests to detect bugs and other issues as soon as they are introduced
+- Static code analysis
+- Deployment
 
 Execute repetitive tasks, save time, and optimize your development process with Jenkins.
 
-== Downloads
+# Downloads
 
 The Jenkins project provides official distributions as WAR files, Docker images, native packages and installers for platforms including several Linux distributions and Windows.
-See the https://www.jenkins.io/download[Downloads] page for references.
+See the [Downloads](https://www.jenkins.io/download) page for references.
 
 For all distributions Jenkins offers two release lines:
 
-* https://www.jenkins.io/download/weekly/[Weekly] -
+- [Weekly](https://www.jenkins.io/download/weekly/) -
   Frequent releases which include all new features, improvements, and bug fixes.
-* https://www.jenkins.io/download/lts/[Long-Term Support (LTS)] -
+- [Long-Term Support (LTS)](https://www.jenkins.io/download/lts/) -
   Older release line which gets periodically updated via bug fix backports.
 
 Latest releases:
-https://www.jenkins.io/changelog[image:https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog%2Fbadge.json[Jenkins Regular Release]]
-https://www.jenkins.io/changelog-stable[image:https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog-stable%2Fbadge.json[Jenkins LTS Release]]
+[![Jenkins Regular Release](https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog%2Fbadge.json)](https://www.jenkins.io/changelog)
+[![Jenkins LTS Release](https://img.shields.io/endpoint?url=https%3A%2F%2Fwww.jenkins.io%2Fchangelog-stable%2Fbadge.json)](https://www.jenkins.io/changelog-stable)
 
-== Source
+# Source
 
-Our latest and greatest source of Jenkins can be found on https://github.com/jenkinsci/jenkins[GitHub]. Fork us!
+Our latest and greatest source of Jenkins can be found on [GitHub](https://github.com/jenkinsci/jenkins). Fork us!
 
-== Contributing to Jenkins
+# Contributing to Jenkins
 
-Follow the link:CONTRIBUTING.adoc[contributing guidelines] if you want to propose a change in the Jenkins core.
+Follow the [contributing guidelines](CONTRIBUTING.md) if you want to propose a change in the Jenkins core.
 For more information about participating in the community and contributing to the Jenkins project,
-see https://www.jenkins.io/participate/[this page].
+see [this page](https://www.jenkins.io/participate/).
 
-Documentation for Jenkins core maintainers is in the link:MAINTAINERS.adoc[maintainers guidelines].
+Documentation for Jenkins core maintainers is in the [maintainers guidelines](docs/MAINTAINERS.adoc).
 
-== News and Website
+# News and Website
 
-All information about Jenkins can be found on our https://www.jenkins.io/[website].
-Follow us on https://twitter.com/jenkinsci[Twitter] or https://www.linkedin.com/company/jenkins-project/[LinkedIn].
+All information about Jenkins can be found on our [website](https://www.jenkins.io/).
+Follow us on [Twitter](https://twitter.com/jenkinsci) or [LinkedIn](https://www.linkedin.com/company/jenkins-project/).
 
-== Governance
+# Governance
 
-See the https://www.jenkins.io/project/governance/[Jenkins Governance Document] for information about the project's open governance, our philosophy and values, and development practices.
-Jenkins Code of Conduct can be found https://www.jenkins.io/project/conduct/[here].
+See the [Jenkins Governance Document](https://www.jenkins.io/project/governance/) for information about the project's open governance, our philosophy and values, and development practices.
+Jenkins Code of Conduct can be found [here](https://www.jenkins.io/project/conduct/).
 
-== Adopters
+# Adopters
 
 Jenkins is used by millions of users and thousands of companies.
-See https://www.jenkins.io/project/adopters/[adopters] for the list of Jenkins adopters and their success stories.
+See [adopters](https://www.jenkins.io/project/adopters/) for the list of Jenkins adopters and their success stories.
 
-== License
+# License
 
-Jenkins is *licensed* under the *https://github.com/jenkinsci/jenkins/blob/master/LICENSE.txt[MIT License]*.
+Jenkins is **licensed** under the **[MIT License](https://github.com/jenkinsci/jenkins/blob/master/LICENSE.txt)**.

MAINTAINERS.adoc → docs/MAINTAINERS.adoc

@@ -307,7 +307,7 @@ triage team members are not responsible for handling the ticket after initial tr
 Other materials which might help:
 
 * link:https://www.jenkins.io/participate/code/[Contribute to Jenkins / Code] or 
-  link:CONTRIBUTING.adoc[Contributing to the Jenkins Core] - 
+  link:https://github.com/jenkinsci/jenkins/blob/master/CONTRIBUTING.md[Contributing to the Jenkins Core] - 
   extended version of "feel free to contribute".
 * link:https://github.com/jenkinsci/.github/blob/master/SUPPORT.md[Jenkins Support Disclaimer Page] -
 for those requesters who expect quick response and SLA.