cli: make revision argument positional for `jj describe`
I missed this command in the previous change.
@@ -643,7 +643,7 @@ fn get_app<'a, 'b>() -> App<'a, 'b> {
.arg(Arg::with_name("no-graph").long("no-graph"));
let describe_command = SubCommand::with_name("describe")
.about("Edit the commit description")
- .arg(rev_arg())
+ .arg(Arg::with_name("revision").index(1).default_value("@"))
.arg(message_arg())
.arg(Arg::with_name("stdin").long("stdin"));
let close_command = SubCommand::with_name("close")
