Erdős Problem 848: status mismatch (repo=formally solved, erdosproblems.com=solved)

The status of [Erdős problem 848]appears to have changed.

- **[This repo](http://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/848.lean)**: `formally solved` (in `FormalConjectures/ErdosProblems/848.lean`)
- **[erdosproblems.com/848](https://www.erdosproblems.com/848)**: `solved`

Please verify and update the `@[category research ...]` annotation if appropriate.

Open FormalConjectures/ErdosProblems/848.lean and inspect its @[category research ...] annotation. Verify the current status against erdosproblems.com/848, then update the annotation if the external status confirms it; the issue is done when the repository metadata matches the verified status.

Written by the indexing model from the issue text.