python legalcode tools update

- cc0_update.py
  - added support for user-specified files (helpful for development)
  - avoid blanklines when there is no diff
- cc4_update.py
  - replaces prep_cc4_code.py and update_cc4_includes.py
  - adds file newline normalization
  - adds languages anchor normalization
  - adds faq translation link normalization
  - improves missing comment insertion

Author: TimidRobot

tools/cc0_update.py

@@ -59,6 +59,8 @@ def diff_changes(filename, old, new):
             n=3,
         )
     )
+    if not diff:
+        return
     # Color diff output
     rst = "\033[0m"
     for i, line in enumerate(diff):
@@ -350,26 +352,42 @@ def setup():
 
     Return argsparse namespace.
     """
+    default_glob = ["zero_1.0*.html"]
     ap = argparse.ArgumentParser(description=__doc__)
     ap.add_argument(
         "-d",
         "--debug",
         action="store_true",
         help="Debug mode: list changes without modification",
     )
+    ap.add_argument(
+        "globs",
+        nargs="*",
+        default=default_glob,
+        help=(
+            "Filename or shell glob of the file(s) that will be updated"
+            f' (default: "{default_glob[0]}")'
+        ),
+        metavar="FILENAME",
+    )
     args = ap.parse_args()
     return args
 
 
 def main():
     args = setup()
     file_list = sorted(
-        [
-            filename
-            for filename in glob.glob("zero_1.0*.html")
-            if os.path.isfile(filename)
-            if not os.path.islink(filename)
-        ]
+        list(
+            set(
+                [
+                    filename
+                    for fileglob in args.globs
+                    for filename in glob.glob(fileglob)
+                    if os.path.isfile(filename)
+                    if not os.path.islink(filename)
+                ]
+            )
+        )
     )
     lang_tags = lang_tags_from_filenames(file_list)
     process_file_contents(args, file_list, lang_tags)