Fix a few doc errors, mostly undefined keywords.
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index d10defb..88655bb 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -634,7 +634,7 @@
imported. The :meth:`find_module` method is called at least with the
absolute name of the module being imported. If the module to be imported is
contained in package then the parent package's :attr:`__path__` attribute
- is passed in as a second argument. The method returns :keyword:`None` if
+ is passed in as a second argument. The method returns ``None`` if
the module cannot be found, else returns a :term:`loader`.
:data:`sys.meta_path` is searched before any implicit default finders or
@@ -687,7 +687,7 @@
A dictionary acting as a cache for :term:`finder` objects. The keys are
paths that have been passed to :data:`sys.path_hooks` and the values are
the finders that are found. If a path is a valid file system path but no
- explicit finder is found on :data:`sys.path_hooks` then :keyword:`None` is
+ explicit finder is found on :data:`sys.path_hooks` then ``None`` is
stored to represent the implicit default finder should be used. If the path
is not an existing path then :class:`imp.NullImporter` is set.