Added content for Markdown stub

src/pages/developer-tools/markdown/index.md

@@ -8,8 +8,17 @@ This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/
 <a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
 
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+Markdown is a lightweight markup language with plain text formatting syntax. It is designed so that it can be converted to HTML and many other formats using a tool by the same name. Markdown is often used to format README files, for writing messages in online discussion forums, and to create rich text using a plain text editor.  You can write Markdown in your text editor too like Sublime Text or Visual Studio Code.
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 #### More Information:
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+A cheatsheet is one of the easiest way to learn Markdown. Check out [this](https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet)  popular cheatsheet.
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+You can also check out this online tutorial: [Markdown Tutorial](https://www.markdowntutorial.com)
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+Love learning by videos? Check out [this Youtube video](https://www.youtube.com/watch?v=HndN6P9ke6U)
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