Updates the multi-model support description in the Coder Research docs
to reference provider companies (Anthropic, xAI, OpenAI) instead of
specific model names (Claude sonnet-4/opus-4, Grok, GPT-5).
This makes the docs more stable as model names change frequently, while
provider names remain constant.
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Co-authored-by: blink-so[bot] <211532188+blink-so[bot]@users.noreply.github.com>
Co-authored-by: Matt Vollmer <matthewjvollmer@outlook.com>