Add better inspector arg parsing (#2642)

sanic/cli/app.py

@@ -148,8 +148,17 @@ Or, a path to a directory to run as a simple HTTP server:
         if unknown:
             for arg in unknown:
                 if arg.startswith("--"):
-                    key, value = arg.split("=")
-                    setattr(self.args, key.lstrip("-"), value)
+                    try:
+                        key, value = arg.split("=")
+                        key = key.lstrip("-")
+                    except ValueError:
+                        value = False if arg.startswith("--no-") else True
+                        key = (
+                            arg.replace("--no-", "")
+                            .lstrip("-")
+                            .replace("-", "_")
+                        )
+                    setattr(self.args, key, value)
 
         kwargs = {**self.args.__dict__}
         host = kwargs.pop("host")

sanic/cli/inspector.py

@@ -47,11 +47,16 @@ def make_inspector_parser(parser: ArgumentParser) -> None:
         action=SanicSubParsersAction,
         dest="action",
         description=(
-            "Run one of the below subcommands. If you have created a custom "
-            "Inspector instance, then you can run custom commands. See ___ "
+            "Run one or none of the below subcommands. Using inspect without "
+            "a subcommand will fetch general information about the state "
+            "of the application instance.\n\n"
+            "Or, you can optionally follow inspect with a subcommand. "
+            "If you have created a custom "
+            "Inspector instance, then you can run custom commands. See "
+            "https://sanic.dev/en/guide/deployment/inspector.html"
             "for more details."
         ),
-        title="Required\n========\n  Subcommands",
+        title="  Subcommands",
         parser_class=InspectorSubParser,
     )
     reloader = subparsers.add_parser(