docs: clarify title handling

README.md

@@ -100,7 +100,7 @@ Key parameters you may want to tune:
 
 - **`question: str | Sequence[str]`** – Query text. Provide a list to batch multiple questions; each item pairs with the corresponding entry in `context`.
 - **`context: str | Sequence[str] | Sequence[Sequence[str]]`** – Contexts aligned to the query. Use a list for one document per query, or a list of lists to supply multiple documents (or pre-split sentences) for each query.
-- **`title: str | Sequence[str] | Sequence[Sequence[str]] | None`** – Optional titles aligned to each context. The default `"first_sentence"` reuses the opening sentence; set `None` to disable automatic extraction.
+- **`title: str | Sequence[str] | Sequence[Sequence[str]] | None`** – Optional titles aligned to each context. The default sentinel `"first_sentence"` marks the opening sentence so you can keep it by pairing with `always_select_title=True` or `first_line_as_title=True`; without those flags it is scored like any other sentence. Set `None` to disable all title handling.
 - **`threshold: float` (default `0.1`)** – Pruning probability cutoff. Larger values discard more sentences; `0.05–0.5` works well across datasets.
 - **`batch_size: int` (default `32`)** – Number of contexts processed per inference batch. Increase for throughput, decrease if you run out of memory.
 - **`language: str | None`** – Built-in splitter selection (`"auto"`, `"ja"`, `"en"`). The default behaves like `"auto"` and detects Japanese vs. English automatically.