fix(complete): Missing options in multi-val arg

jj dynamic completions of option names work as expected:

	$ COMPLETE=fish jj -- jj abandon --ignore-
	--ignore-working-copy
	--ignore-immutable

Unless there is a positional argument preceding the option

	$ COMPLETE=fish jj -- jj abandon @ --ignore-

The positional arguments are defined in the "abandon" subcommand as:

```rust
#[derive(clap::Args, Clone, Debug)]
pub(crate) struct AbandonArgs {
    /// The revision(s) to abandon (default: @)
    #[arg(value_name = "REVSETS")]
    revisions_pos: Vec<RevisionArg>,
}
```

Fix that in most cases.

Fixes #5935

Author: krobelus

clap_complete/src/engine/complete.rs

@@ -159,12 +159,18 @@ fn complete_arg(
             }
             completions.extend(complete_option(arg, cmd, current_dir));
         }
-        ParseState::Pos(..) => {
+        ParseState::Pos((_, num_arg)) => {
             if let Some(positional) = cmd
                 .get_positionals()
                 .find(|p| p.get_index() == Some(pos_index))
             {
                 completions.extend(complete_arg_value(arg.to_value(), positional, current_dir));
+                if positional
+                    .get_num_args()
+                    .is_some_and(|num_args| num_arg >= num_args.min_values())
+                {
+                    completions.extend(complete_option(arg, cmd, current_dir));
+                }
             }
         }
         ParseState::Opt((opt, count)) => {

clap_complete/tests/testsuite/engine.rs

@@ -813,7 +813,13 @@ pos_2
 "#]]
     );
 
-    assert_data_eq!(complete!(cmd, "pos_1 pos_2 --[TAB]"), snapbox::str![""]);
+    assert_data_eq!(
+        complete!(cmd, "pos_1 pos_2 --[TAB]"),
+        snapbox::str![[r#"
+--format
+--help	Print help
+"#]]
+    );
     assert_data_eq!(
         complete!(cmd, "pos_1 pos_2 --format json [TAB]"),
         snapbox::str![[r#"