Rule: `label` must reference control

Rule ID	Control 6
Conformance	Required
Definition	Each `label` element using the `for` attribute must reference a form control on the page.
Purpose	`label` elements are useful for accessibility only when they reference form controls. The use of labels increase the effective size for activation of the control and provide a speak-able label for speech input activation.
Conformance	Required
WCAG Success Criteria	Success Criterion 3.3.2 Labels or Instructions Other Related Success Criterion: Success Criterion 1.3.1 Info and Relationships Success Criterion 2.4.6 Headings and Labels
Rule Category	Forms
Rule Scope	Element
Techniques	For a `label` element to properly reference a form control, ensure that the `for` attribute value on the `label` element exactly matches the `id` attribute value on the form control.
Information Links	HTML Specification: The @label@ element @for@ attribute W3C WAI Accessibility Tutorials: Forms Concepts H44: Using label elements to associate text labels with form controls

Rule: label must reference control