Added nano to text editor list.

README.md

@@ -141,6 +141,7 @@ Only main chapters:
 &nbsp;&nbsp;:small_orange_diamond: <a href="http://ex-vi.sourceforge.net/"><b>vi</b></a> - is one of the most common text editors on Unix.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.vim.org/"><b>vim</b></a> - is a highly configurable text editor.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.gnu.org/software/emacs/"><b>emacs</b></a> - is an extensible, customizable, free/libre text editor - and more.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.nano-editor.org/"><b>nano</b></a> - is a basic, standard text editor that is available on most linux systems by default.<br>
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