Rework LICENSE files for GitHub

Hopefully this is still clear and will show up better in the GitHub UI.

COPYING.txt

@@ -1,7 +1,15 @@
-This repository is licensed Apache-2.0 except for
-the docs/ directory which is mostly licensed CC-BY-SA-4.0 instead.
+# Notice Regarding Separate Licensing #
+
+Although this repository contains the LICENSE.Apache-2.0.txt file,
+FILES WITHOUT THE "SPDX-License-Identifier: Apache-2.0" COMMENT
+ARE EXCLUDED FROM THE LICENSE.
+
+The docs/ directory is mostly licensed CC-BY-SA-4.0 instead.
+See the docs/LICENSE.CC-BY-SA-4.0.txt file for the full text of that license.
+
 Which license applies is noted inside each file near the top.
 
-See the setup/LICENSE.txt and docs/CC-BY-SA-4.0.txt files for the full text of each license.
+The docs/hissp.svg and docs/H.svg logos are trademarks.
 
-The docs/hissp.svg and docs/H.svg logos are trademarks.
+(Hissp package-only distributions do not include the extra documentation
+or this notice.)

setup.py

@@ -2,10 +2,13 @@
 # Copyright 2019, 2020, 2021, 2022, 2023 Matthew Egan Odendahl
 # SPDX-License-Identifier: Apache-2.0
 import os
+import shutil
 import sys
 
 import setuptools
 
+os.makedirs("setup", exist_ok=True)
+shutil.copy("LICENSE.Apache-2.0.txt", "setup/LICENSE.txt")
 os.chdir("setup")
 
 with open("../README.md", encoding="utf8") as f: