Should mention that the sum of `maxInputTokens` and `maxOutputTokens` must be less than or equal to the context window.

[tamuratak]

Should mention that the sum of maxInputTokens and maxOutputTokens must be less than or equal to the context window for the setting of BYOK models.

• https://code.visualstudio.com/docs/agent-customization/language-models#_model-configuration-reference

Although it is implicitly explained in the code sample of the extension API document, we should explicitly explain in the BYOK setting document.

• https://code.visualstudio.com/api/extension-guides/ai/language-model-chat-provider#prepare-language-model-information

        maxInputTokens: model.contextWindow - model.maxOutput,

Context:

• Custom Endpoints with finish_reason: "length" violently crash with "Response too long" instead of rendering generated text vscode#319592 (comment)