`sub+sup` element

Pass Criteria

#1: Elements are supported
#2: Correct HTML and Core Accessibility API mappings
#3: Correct Accessible Name & Description Calculation

Reference

Test ss-001: `sub` element

H₂0 - Water

O₂ - Oxygen

CO₂ - Carbon Dioxide

Test ss-002: `sup` element

HTML was published as a Recommendation on the 28^th of October 2014.