Document preference towards LF in `unfill`
@@ -601,11 +601,17 @@ where
/// textwrap: a small library for wrapping text.
/// ```
///
-/// In addition, it will recognize a common prefix among the lines.
+/// In addition, it will recognize a common prefix and a common line
+/// ending among the lines.
+///
/// The prefix of the first line is returned in
/// [`Options::initial_indent`] and the prefix (if any) of the the
/// other lines is returned in [`Options::subsequent_indent`].
///
+/// Line ending is returned in [`Options::line_ending`]. If line ending
+/// can not be confidently detected (mixed or no line endings in the
+/// input), [`LineEnding::LF`] will be returned.
+///
/// In addition to `' '`, the prefixes can consist of characters used
/// for unordered lists (`'-'`, `'+'`, and `'*'`) and block quotes
/// (`'>'`) in Markdown as well as characters often used for inline
