Document userProvided embedders have no templates

[ellnix]

Really small thing, didn't make an issue for it.

curl \
  -X PATCH 'localhost:7700/indexes/books/settings/embedders' \
  -H 'Content-Type: application/json' \
  --data-binary '{
    "default": {
      "source":  "userProvided",
      "documentTemplate": "heya",
      "dimensions": 3
    }
  }' \
-H 'Authorization: Bearer masterKey'

{
  "message": "`.embedders.default`: Field `documentTemplate` unavailable for source `userProvided` (only available for sources: `huggingFace`, `openAi`, `ollama`, `rest`). Available fields: `source`, `dimensions`, `distribution`, `binaryQuantized`",
  "code": "invalid_settings_embedders",
  "type": "invalid_request",
  "link": "https://docs.meilisearch.com/errors#invalid_settings_embedders"
}

[guimachiavelli]

Thanks, @ellnix! 🙇