docs: Add voice and tone guide for marketing copy

[ericholscher]

Add a comprehensive voice and tone guide for Read the Docs marketing copy, including blog posts, site pages, newsletters, announcements, and CTAs.

This guide documents our existing house style and makes it repeatable across all marketing and public-facing communication. It covers:

• Brand personality: Five adjectives that define our voice (Direct, Credible, Honest, Grounded, Warm)
• Core voice principles: Eight foundational principles including leading with benefits, proving claims with specifics, and being honest about hard things
• Tone by context: A reference table for adjusting tone across different situations (homepage, announcements, deprecations, incidents, etc.)
• Language patterns: Specific words and phrases we use and avoid, plus grammar and mechanics guidelines
• Quick checklist: Pre-publishing verification steps to ensure consistency

The guide emphasizes our differentiators as a bootstrapped, open source company: transparency, respect for both commercial and open source audiences, and substance-driven communication without hype.

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Generated by AI

https://claude.ai/code/session_01VBMdiFnopLRWSTmt2qhPj7

[davidfischer]

This looks great!