lib.Cmd.AbstractCmd.aliases: Add property

Add a property aliases to AbstractCmd in prepeparation for commands to bear multiple names / abbreviations / aliases.
The App.add_cmds_to_parser() function uses parse_known_args() to determine which subcommand was invoked, then conditionally registers nested subcommands. The lookup dictionary (scs) contains only canonical names, not aliases, so add them too, otherwise using the alias instead of the canonical name causes the lookup to fail and nested subcommands to never be registered.
Fix: Register each alias in scs pointing to the same SubCommand object, and deduplicate with id(sc) when iterating in all=True mode to avoid infinite recursion on help output.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/cmds/Cmd.py

@@ -6,12 +6,19 @@ from ..App import App as Parent
 from ..CmdBase import CmdBase as Base
 
 if TYPE_CHECKING:
+    from typing import Iterable
     from ..lib.Distro import Distro
 
 class Cmd(Base):  # export
 
-    def __init__(self, parent: Parent, name: str, help: str) -> None:
-        super().__init__(parent, name, help)
+    def __init__(
+        self,
+        parent: Parent,
+        name: str,
+        help: str,
+        aliases: Iterable[str] | None = None
+    ) -> None:
+        super().__init__(parent, name, help, aliases = aliases)
 
     async def _run(self, args):
         # Missing subcommand