text: Title: Improve search for alternative backends/clients
  Body: Ideas based on https://pydanticlogfire.slack.com/archives/C06EDRBSAH3/p1728466950149999:
  
  1. Searching for "opentelemetry" should return https://logfire.pydantic.dev/docs/guides/advanced/alternative-clients/ and https://logfire.pydantic.dev/docs/guides/advanced/alternative-backends/ as the first results
  2. https://logfire.pydantic.dev/docs/guides/advanced/alternative-backends/ should mention the word 'server' and any other keywords likely to be searched
  3. https://logfire.pydantic.dev/docs/why-logfire/opentelemetry/ should link to both those pages.
  4. https://logfire.pydantic.dev/docs/why-logfire/opentelemetry/ should make the alternative clients point clearer - I think that's what "supports cross-language data integration" is trying to say but I'm not sure.