Init rst cheatsheet

intro/contribution/index.rst

@@ -88,3 +88,4 @@ Style and usage guidelines
 
    /intro/contribution/git-usage
    /intro/contribution/style
+   /intro/contribution/rst-cheat-sheet

intro/contribution/rst-cheat-sheet.rst

+.. _rst-cheat-sheet:
+
+ReStructuredText Cheat Sheet
+############################
+
+BeagleBoard docs is mostly writted with ReStructuredText (r)
+
+Headings
+*********
+
+For each document we divide sections with headings and in ReStructuredText we can use 
+matching overline and underline to indicate a heading. 
+
+1. Document heading (H1) use ``#``.
+2. First heading (H2) use ``*``.
+3. First heading (H2) use ``=``.
+4. First heading (H2) use ``-``.
+5. First heading (H2) use ``~``.
+
+.. note::
+    You can include only one (H1) ``#`` in a single documentation page.
+
+Make sure the length of your heading symbol is atleast (or 
+more) the lenth of the heading text, for example:
+
+
+.. callout::
+
+    .. code-block:: ReStructuredText
+
+        incorrect H1
+        ##### # <1>
+
+        correct H1
+        ############ # <2>
+    
+    .. annotations::
+
+        <1> length of heading sybol ``#`` is smaller than the content above.
+        <2> Shows the correct way of setting the document title (H1) with ``#``.
+
+    
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