Add documentation additionally to the help page of qute-pass (complaint from the Arch wiki)

misc/userscripts/qute-pass

@@ -44,8 +44,16 @@ import sys
 
 import tldextract
 
-argument_parser = argparse.ArgumentParser()
-argument_parser.add_argument('url', nargs='?', default=os.environ['QUTE_URL'])
+argument_parser = argparse.ArgumentParser(description=(
+    'Insert login information using pass and a dmenu-provider (e.g. dmenu, rofi -dmenu, ...). A short '
+    'demonstration can be seen here: https://i.imgur.com/KN3XuZP.gif.'), usage=(
+    'The domain of the site has to appear as a segment in the pass path, for example: "github.com/cryzed" or '
+    '"websites/github.com". How the username and password are determined is freely configurable using the CLI '
+    "arguments. The login information is inserted by emulating key events using qutebrowser's fake-key command in this "
+    'manner: [USERNAME]<Tab>[PASSWORD], which is compatible with almost all login forms.'), epilog=(
+    "WARNING: The login details are viewable as plaintext in qutebrowser's debug log (qute://log) and might be shared "
+    'if you decide to submit a crash report!'))
+argument_parser.add_argument('url', nargs='?', default=os.getenv('QUTE_URL'))
 argument_parser.add_argument('--password-store', '-p', default=os.path.expanduser('~/.password-store'),
                              help='Path to your pass password-store')
 argument_parser.add_argument('--username-pattern', '-u', default=r'.*/(.+)',
@@ -71,6 +79,7 @@ stderr = functools.partial(print, file=sys.stderr)
 
 class ExitCodes(enum.IntEnum):
     SUCCESS = 0
+    FAILURE = 1
     # 1 is automatically used if Python throws an exception
     NO_PASS_CANDIDATES = 2
     COULD_NOT_MATCH_USERNAME = 3
@@ -108,6 +117,10 @@ def dmenu(items, invocation, encoding):
 
 
 def main(arguments):
+    if not arguments.url:
+        argument_parser.print_help()
+        return ExitCodes.FAILURE
+
     extract_result = tldextract.extract(arguments.url)
 
     # Expand potential ~ in paths, since this script won't be called from a shell that does it for us