Update docs index.rst

Added a link to Atom syntax highlighting

docs/index.rst

@@ -65,11 +65,13 @@ Syntax Highlighting
 -  `Visual Studio Code`_ (Or install through the vscode plugin system)
 -  `Intellij & PyCharm`_
 -  `Vim`_
+-  `Atom`
 
 .. _Sublime Text & TextMate: https://github.com/lark-parser/lark_syntax
 .. _Visual Studio Code: https://github.com/lark-parser/vscode-lark
 .. _Intellij & PyCharm: https://github.com/lark-parser/intellij-syntax-highlighting
 .. _Vim: https://github.com/lark-parser/vim-lark-syntax
+.. _Atom: https://github.com/Alhadis/language-grammars
 
 Resources
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