Tidy up some build warnings (pypa#435)

Author: ncoghlan

source/guides/analyzing-pypi-package-downloads.rst

@@ -23,20 +23,23 @@ collect and display accurately. Reasons for this are included in the
     of which are:
 
         - Technically hard to make work with the new CDN
+
             - The CDN is being donated to the PSF, and the donated tier does
               not offer any form of log access
             - The work around for not having log access would greatly reduce
               the utility of the CDN
         - Highly inaccurate
             - A number of things prevent the download counts from being
               inaccurate, some of which include:
+
                 - pip download cache
                 - Internal or unofficial mirrors
                 - Packages not hosted on PyPI (for comparisons sake)
                 - Mirrors or unofficial grab scripts causing inflated counts
                   (Last I looked 25% of the downloads were from a known
                   mirroring script).
         - Not particularly useful
+
             - Just because a project has been downloaded a lot doesn't mean
               it's good
             - Similarly just because a project hasn't been downloaded a lot

source/specifications/core-metadata.rst

@@ -360,7 +360,7 @@ Examples::
     License: GPL version 3, excluding DRM provisions
 
 
-.. _metadata_classifier:
+.. _metadata-classifier:
 
 Classifier (multiple use)
 =========================

source/tutorials/installing-packages.rst

@@ -63,7 +63,7 @@ please install the latest 3.x version from `python.org`_ or refer to the
     can run system commands like those in this tutorial by prefacing them with
     a ``!`` character:
 
-    .. code-block:: python
+    ::
 
         In [1]: !python --version
         Python 3.6.3