add markdown help

docs/markdown/cheatsheet.md

@@ -0,0 +1,71 @@
+categories: markdown
+title: Aide
+
+# Markdown cheat sheet
+
+## Headers
+
+# This is a Heading h1
+## This is a Heading h2
+###### This is a Heading h6
+
+## Emphasis
+
+*This text will be italic*  
+_This will also be italic_
+
+**This text will be bold**  
+__This will also be bold__
+
+_You **can** combine them_
+
+## Lists
+
+### Unordered
+
+* Item 1
+* Item 2
+* Item 2a
+* Item 2b
+
+### Ordered
+
+1. Item 1
+2. Item 2
+3. Item 3
+    1. Item 3a
+    2. Item 3b
+
+## Images
+
+![This is an alt text.](/image/sample.webp "This is a sample image.")
+
+## Links
+
+You may are using [Brainsys' Wiki](https://wiki.brainsys.io/).
+
+## Blockquotes
+
+> Markdown is a lightweight markup language with plain-text-formatting syntax, created in 2004 by John Gruber with Aaron Swartz.
+>
+>> 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.
+
+## Tables
+
+| Left columns  | Right columns |
+| ------------- |:-------------:|
+| left foo      | right foo     |
+| left bar      | right bar     |
+| left baz      | right baz     |
+
+## Blocks of code
+
+```
+let message = 'Hello world';
+alert(message);
+```
+
+## Inline code
+
+This web site is using `mkdocs`.
+