[RestructuredText] single quotes break link targets

[jrappen]

Same issue as the GFM-rendered codeblock below:

Bla bla bla `link target a`_ bla bla `link b's target`_ bla bla.

.. _link target a: https://github.com/sublimehq/Packages/blob/master/README.md#installation
.. _link b's target: https://github.com/sublimehq/Packages/blob/master/README.md#installation