Fixed minor documentation errors and mistakes (#151)

doc/development/contribution/general.rst

@@ -20,11 +20,11 @@ on our `GitHub repository`_.
 
 Before you do so, please `squash all your changes`_ into one single commit. Please
 use the test suite to check whether your changes break any existing features and run
-the code style checks to confirm you are consistent with pretix' coding style. You'll
+the code style checks to confirm you are consistent with pretix's coding style. You'll
 find instructions on this in the :ref:`checksandtests` section of the development setup guide.
 
 We automatically run the tests and the code style check on every pull request on Travis CI and we won’t
-accept any pull requets without all tests passing. However, if you don't find out *why* they are not passing,
+accept any pull requests without all tests passing. However, if you don't find out *why* they are not passing,
 just send the pull request and tell us – we'll be glad to help.
 
 If you add a new feature, please include appropriate documentation into your patch. If you fix a bug,
@@ -34,4 +34,4 @@ Again: If you get stuck, do not hesitate to contact any of us, or Raphael person
 
 .. _create a pull request: https://help.github.com/articles/creating-a-pull-request/
 .. _GitHub repository: https://github.com/pretix/pretix
-.. _squash all your changes: https://davidwalsh.name/squash-commits-git
+.. _squash all your changes: https://davidwalsh.name/squash-commits-git

doc/development/contribution/style.rst

@@ -6,7 +6,7 @@ Python code
 
 * Basically: Follow `PEP 8`_.
 
-  Use `flake8`_ to check for conformance problems. The project includes a setup.cfg
+  Use `flake8`_ to check for conformance problems. The project includes a setup.cfg file
   with a default configuration for flake8 that excludes migrations and other non-relevant
   code parts. It also silences a few checks, e.g. ``N802`` (function names should be lowercase) 
   and increases the maximum line length to more than 79 characters. **However** you should