Cleanup jsonify() function

Cleanup some leftover stuff from pallets#1671. PEP8 spacing, args/kwargs don't need to be converted to list/dict, and Sphinx formatting.

CHANGES

@@ -10,7 +10,7 @@ Version 1.0
 
 - Added support to serializing top-level arrays to :func:`flask.jsonify`. This
   introduces a security risk in ancient browsers. See
-  :ref:`json_security` for details.
+  :ref:`json-security` for details.
 - Added before_render_template signal.
 - Added `**kwargs` to :meth:`flask.Test.test_client` to support passing
   additional keyword arguments to the constructor of

flask/json.py

@@ -211,9 +211,9 @@ def jsonify(*args, **kwargs):
 
     1. Single argument: Passed straight through to :func:`dumps`.
     2. Multiple arguments: Converted to an array before being passed to
-    :func:`dumps`.
+       :func:`dumps`.
     3. Multiple keyword arguments: Converted to a dict before being passed to
-    :func:`dumps`.
+       :func:`dumps`.
     4. Both args and kwargs: Behavior undefined and will throw an exception.
 
     Example usage::
@@ -237,7 +237,7 @@ def get_current_user():
 
     .. versionchanged:: 1.0
        Added support for serializing top-level arrays. This introduces a
-       security risk in ancient browsers. See :ref:`json_security` for details.
+       security risk in ancient browsers. See :ref:`json-security` for details.
 
     This function's response will be pretty printed if it was not requested
     with ``X-Requested-With: XMLHttpRequest`` to simplify debugging unless
@@ -260,12 +260,10 @@ def get_current_user():
         raise TypeError(
             "jsonify() behavior undefined when passed both args and kwargs"
         )
-    elif len(args) == 1: # single args are passed directly to dumps()
+    elif len(args) == 1:  # single args are passed directly to dumps()
         data = args[0]
-    elif args: # convert multiple args into an array
-        data = list(args)
-    else: # convert kwargs to a dict
-        data = dict(kwargs)
+    else:
+        data = args or kwargs
 
     # Note that we add '\n' to end of response
     # (see https://github.com/mitsuhiko/flask/pull/1262)