[3.14] Fix mixed line endings with pre-commit (GH-148336)

(cherry picked from commit fc5df4d)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Zachary Ware <zachary.ware@gmail.com>

Author: hugovk

.pre-commit-config.yaml

@@ -77,6 +77,9 @@ repos:
         exclude: Lib/test/tokenizedata/coding20731.py
       - id: end-of-file-fixer
         files: '^\.github/CODEOWNERS$'
+      - id: mixed-line-ending
+        args: [--fix=auto]
+        exclude: '^Lib/test/.*data/'
       - id: trailing-whitespace
         types_or: [c, inc, python, rst, yaml]
       - id: trailing-whitespace