Suggestion: rename llms.txt to robots.md

LLM is just one AI technology (with wide use/success, of course), but new technologies are likely to emerge in the not-so-distant future that are not (primarily) based on large language models. Thus, I suggest using something more generic than `llm` in the resource name, or this resource will feel dated/quaint or even obsolete in a few years. Additionally, non-AI, non-LLM consumers (browser plugins, aggregators) may be able to benefit from this resource as well.

`robots.txt` is pretty generic and does not limit/constrain or even name the technology used to scan/crawl web sites.

Perhaps `robots.md` would work here? This also conveys the fact that the content is Markdown, not just text.

The issue names no files, tests, or entry points. Start by surveying the repository for references to llms.txt and the naming convention, then confirm whether the project has chosen a replacement; done means the decision and any required references are consistent.

Written by the indexing model from the issue text.