Capabilities Opening Paragraphs

A few weeks ago we identified capabilities in our document which were missing their introductory paragraphs. These have now been added. Please review:

3.1.3: Ensure Keyboard Access to Interactive Elements
3.2.7: Drop Cap Implementation
3.4.2: Personalize Color Palette
3.5.1: Styled Lists
3.5.2: Text Box Framing
3.5.3: Shadow and Outline Effects
3.5.4: Text Transparency Control
... 4.2: User Authentication
... 4.4.3: Managing Time Outs
4.4.4: Validate Form Content Accessibly
4.5.1: Expose Structural Semantics
... 4.5.2: Handle Dynamic Pages Accessibly
... 4.5.3: Correct Semantic Behavior
... 4.6.6: Ensure Nested Text Element Accessibility
... 4.6.7: Support ARIA Roles & Attributes
4.6.8: Voice Command
... 4.7.5: Provide Appropriate Acronym Expansion with TTS