Add a NEST documentation style guide

doc/userdoc/contribute/index.rst

@@ -9,7 +9,8 @@ Please familiarize yourself with our:
 
 * :doc:`NEST Git workflow <development_workflow>`
 * :doc:`C++ coding style guidelines <coding_guidelines_cpp>`
-* :doc:`Developing NEST with IDEs <nest_with_ides>`
+* :doc:`Documentation style guide <templates_styleguides/styleguide>`
+* :doc:`Developing NEST with IDEs guide <nest_with_ides>`
 
 In order to make sure that the NEST Initiative can manage the NEST code base in the long term,
 you need to send us a completed and signed
@@ -24,6 +25,8 @@ If you find an error in the code or documentaton or want to suggest a feature, s
 
 Make sure to check that your issue has not already been reported there before creating a new one.
 
+.. _edit_nest:
+
 Change code or documentation
 ----------------------------
 

doc/userdoc/contribute/styleguide/sample_doc.rst

@@ -0,0 +1,18 @@
+Main title of document
+======================
+
+
+.. _sec_my-ref-label:
+
+Section to cross-reference
+--------------------------
+
+Some content in this section.
+
+
+
+.. _eq_my-arbitrary-place-label:
+
+.. math::
+
+    e = mc^2