Document that prompt character limit is 1000 characters

[adaboese]

https://github.com/Leonardo-Interactive/leonardo-ts-sdk/blob/main/docs/sdk/models/operations/creategenerationrequestbody.md

Should say somewhere hear.

If prompt is longer than 1000 character, the response is just 400.

Here is an example prompt taken from aimd.app:

{
  "height": 768,
  "num_images": 1,
  "prompt": "## Subject and Composition\n\nA stack of books with a magnifying glass hovering above, peering down at the top book titled \"Topical Authority in SEO.\" Each book represents different aspects of SEO—keywords, backlinks, and content production, with clear, bold titles etched on their spines. In the background, digital icons symbolizing Google's algorithm are artfully arranged to suggest a pathway leading towards the horizon and therefore success. The magnifying glass denotes focused research, contributing to the sense of expertise and trustworthiness.\n\n## Action, State, and Mood\n\nThe magnifying glass is tilting slightly, signifying the action of analyzing or enhancing focus on the topic at hand. The state of the books is used and slightly worn, suggesting they've been studied extensively. The mood is studious and determined, infused with an air of optimism and ambition.\n\n## Artistic Style\n\nA digital illustration mimicking a modernist style, employing bold colors and simple geometric forms. The clean lines and disciplined arrangement are faintly reminiscent of Bauhaus design principles.\n\n## Setting Details\n\nThe setting merges a traditional study with digital elements. Indoor lighting with a spotlight effect on the stack of books and magnifying glass, while the rest of the image is bathed in a gradient from warm yellow to cool blue, representing the transition from traditional SEO towards the new EEAT paradigm.\n\n## Desired Impact or Message\n\nThe viewer should feel a sense of enlightenment, perceiving a clear path to achieving topical authority in the realm of SEO. They should understand that SEO is multifaceted and that through diligent study and the application of these principles, they can build expertise, authority, and trustworthiness in their niche. The overall impression should be one of empowerment and readiness to embrace the modern SEO tactics described in the paragraph.",
  "promptMagic": false,
  "width": 1024
}

and repsonse:

>   contentType: 'application/json; charset=utf-8',
>   statusCode: 400,
>   rawResponse: {
>     status: 400,
>     statusText: 'Bad Request',