Use Py3+ autoformat configs

.isort.cfg

@@ -1,7 +1,6 @@
 [settings]
 default_section = THIRDPARTY
 known_first_party = hypothesis, hypothesistooling, tests
-add_imports = from __future__ import absolute_import, from __future__ import print_function, from __future__ import division
 multi_line_output = 3
 include_trailing_comma = True
 force_grid_wrap = 0

tooling/src/hypothesistooling/__main__.py

@@ -153,8 +153,6 @@ def deploy():
 
 
 HEADER = """
-# coding=utf-8
-#
 # This file is part of Hypothesis, which may be found at
 # https://github.com/HypothesisWorks/hypothesis/
 #
@@ -239,12 +237,12 @@ def should_format_doc_file(path):
         "--remove-unused-variables",
         *files_to_format,
     )
-    pip_tool("pyupgrade", "--keep-percent-format", *files_to_format)
+    pip_tool("pyupgrade", "--keep-percent-format", "--py3-plus", *files_to_format)
     pip_tool("isort", *files_to_format)
-    pip_tool("black", *files_to_format)
+    pip_tool("black", "--target-version=py35", *files_to_format)
 
 
-VALID_STARTS = ("# coding=utf-8", "#!/usr/bin/env python")
+VALID_STARTS = (HEADER.split()[0], "#!/usr/bin/env python")
 
 
 @task()