Accurate, timeless headers

Per advice from the Linux Foundation, we can keep this short and don't need to list years.

This also removes some stale information such as the authors file, and universal attribution to David.  He wrote much of Hypothesis, but there are also large parts he's never touched!

Author: Zac-HD

tooling/src/hypothesistooling/__main__.py

@@ -18,7 +18,6 @@
 import re
 import subprocess
 import sys
-from datetime import datetime
 from glob import glob
 from urllib.parse import urlparse
 
@@ -142,24 +141,18 @@ def deploy():
     sys.exit(0)
 
 
-CURRENT_YEAR = datetime.utcnow().year
-
-
-HEADER = f"""
+# See https://www.linuxfoundation.org/blog/copyright-notices-in-open-source-software-projects/
+HEADER = """
 # This file is part of Hypothesis, which may be found at
 # https://github.com/HypothesisWorks/hypothesis/
 #
-# Most of this work is copyright (C) 2013-{CURRENT_YEAR} David R. MacIver
-# (david@drmaciver.com), but it contains contributions by others. See
-# CONTRIBUTING.rst for a full list of people who may hold copyright, and
-# consult the git log if you need to determine who owns an individual
-# contribution.
+# Copyright the Hypothesis Authors.
+# Individual contributors are listed in AUTHORS.rst and the git log.
 #
 # This Source Code Form is subject to the terms of the Mozilla Public License,
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
-#
-# END HEADER""".strip()
+""".strip()
 
 
 @task()
@@ -197,22 +190,23 @@ def warn(msg):
     config.from_file(os.path.join(hp.BASE_DIR, ".coveragerc"), warn=warn, our_file=True)
     pattern = "|".join(l for l in config.exclude_list if "pragma" not in l)
     unused_pragma_pattern = re.compile(f"(({pattern}).*)  # pragma: no (branch|cover)")
+    last_header_line = HEADER.splitlines()[-1].rstrip()
 
     for f in files_to_format:
         lines = []
         with open(f, encoding="utf-8") as o:
             shebang = None
             first = True
-            header_done = False
+            in_header = True
             for l in o.readlines():
                 if first:
                     first = False
                     if l[:2] == "#!":
                         shebang = l
                         continue
-                if "END HEADER" in l and not header_done:
+                elif in_header and l.rstrip() == last_header_line:
+                    in_header = False
                     lines = []
-                    header_done = True
                 else:
                     lines.append(unused_pragma_pattern.sub(r"\1", l))
         source = "".join(lines).strip()