## Problem
Issue #2247 notes that the Python docs do not show how to use LanceDB's
in-memory backend via `connect("memory://")`.
## Solution
Add `memory://` examples to the sync and async `connect` docstrings, and
call out that in-memory databases are intended for tests/temporary data
and are not persisted.
## Validation
- `python3 -m py_compile python/python/lancedb/__init__.py`
- `git diff --check`
## Confidence
82/100 — docs-only update, directly tied to the documented missing
`memory://` usage. It changes API documentation only and was syntax/diff
validated.
Closes#2247.
