Document newline behavior of `file-contents-sorter`

README.md

diff --git a/README.md b/README.md
index 1ebba89..5089227 100644
--- a/README.md
+++ b/README.md
@@ -117,6 +117,7 @@
 Sort the lines in specified files (defaults to alphabetical).
 You must provide the target [`files`](https://pre-commit.com/#config-files) as input.
 Note that this hook WILL remove blank lines and does NOT respect any comments.
+All newlines will be converted to line feeds (`\n`).
 
 The following arguments are available:
 - `--ignore-case` - fold lower case to upper case characters.