`missing-name` lint check never triggered

[muzimuzhi]

A usage spec with no name nor bin (learnt from #430) still didn't trigger the missing-name lint check.

usage/cli/src/cli/lint.rs

Lines 131 to 139 in 9969499

	// Check spec-level issues
	if spec.bin.is_empty() && spec.name.is_empty() {
	issues.push(LintIssue {
	severity: Severity::Warning,
	code: "missing-name".to_string(),
	message: "Spec has no name or bin defined".to_string(),
	location: None,
	});
	}

$ echo 'arg "<file>" help="The file to process"' > myscript.usage.kdl
$ usage lint myscript.usage.kdl
No issues found.

$ usage --version
usage-cli 5.0.0