Cleanup: documentation .rst files

docs/source/backends/json.rst

@@ -86,4 +86,3 @@ when picking the JSON backend:
 
 .. literalinclude:: json_example.json
    :language: json
-

docs/source/citation.rst

@@ -90,4 +90,3 @@ Python
          .format(io.__version__))
    print("openPMD-api backend variants: {}"
          .format(io.variants))
-

docs/source/dev/sphinx.rst

@@ -66,4 +66,3 @@ Useful Links
  * `A primer on writing restFUL files for sphinx <http://www.sphinx-doc.org/en/stable/rest.html>`_
  * `Why You Shouldn't Use "Markdown" for Documentation <http://ericholscher.com/blog/2016/mar/15/dont-use-markdown-for-technical-docs/>`_
  * `Markdown Limitations in Sphinx <https://docs.readthedocs.io/en/latest/getting_started.html#in-markdown>`_
-

docs/source/usage/streaming.rst

@@ -92,4 +92,4 @@ Note that a closed iteration cannot be reopened.
 This pays tribute to the fact that in streaming mode, an iteration is sent to the sink upon closing it and the data source can no longer modify it.
 
 .. literalinclude:: 10_streaming_write.py
-   :language: python3
+   :language: python3

docs/source/utilities/cli.rst

@@ -48,4 +48,4 @@ With some ``pip``-based python installations, you might have to run this as a mo
 
 .. code-block:: bash
 
-   python -m openpmd_api.pipe --help
+   python -m openpmd_api.pipe --help