Add FAQ / tl;dr at the beginning of the document

[mvonballmo]

Observed

The document is quite long and doesn't provide very much of a summary of the rules most important to developers.

Expected

The document should include an FAQ with links into the rest of the document that complements the TOC with another way of getting into the material.

Analysis

Add sections for the following questions (to begin with):

• Should I use global namespaces?
• Should I use var?
• Should I use records? When?
• Should I use record structs? When?