doc: Update contributing guide

CONTRIBUTING.rst

@@ -7,31 +7,30 @@ Thank you for interested to ``sphinx-revealjs``.
 If you are
 ==========
 
+.. _Discussions: https://github.com/attakei/sphinx-revealjs/discussions
+
 using
 -----
 
 Please share and publish about using (I am glad for it!).
 
-aving questions
----------------
+having questions or suggesting bugs
+-----------------------------------
+
+Please post into `Discussions`_.
 
-Please post `Discussions <https://github.com/attakei/sphinx-revealjs/discussions>`_.
+If this is bug of sphinx-revealjs, I create as `issue <https://github.com/attakei/sphinx-revealjs/issues>`_.
 
 find typo in sources, doc and demo
 ----------------------------------
 
 Please post `PR <https://github.com/attakei/sphinx-revealjs/pulls>`_ directly (not need create issue).
 
-find bugs in sources
---------------------
-
-Please create `issue <https://github.com/attakei/sphinx-revealjs/issues>`_ first.
-
 want features for this
 ----------------------
 
 1. Please think first: "Does features that you want have deep-dependency for sphinx-revealjs?".
-1. If features need based-on sphinx-revealjs, please create issue.
+1. If features need based-on sphinx-revealjs, please post into `Discussions`_.
 1. I think about "does this need for sphinx-revealjs", but I not always implement/accept PR for it.
 
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