Enforce LF line endings for Markdown files (#60350)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: 3 people

.gitattributes

@@ -1,7 +1,7 @@
 # Set default behavior, in case users don't have core.autocrlf set.
 * text=auto
-# Explicitly declare text files we want to always be normalized and converted
-# to native line endings on checkout.
-*.md text diff=markdown
+# Explicitly declare text files we want to always be normalized, and for
+# Markdown files, enforce LF line endings on checkout.
+*.md text eol=lf diff=markdown
 *.json.br filter=lfs diff=lfs merge=lfs -text
 .github/workflows/*.lock.yml linguist-generated=true merge=ours