chore: normalize line endings (CRLF -> LF)

No content changes: git diff --ignore-all-space over these files is empty.
The churn came from editing on Windows against a repo checked out with LF.

linux/runner/my_application.h

@@ -1,21 +1,21 @@
-#ifndef FLUTTER_MY_APPLICATION_H_
-#define FLUTTER_MY_APPLICATION_H_
-
-#include <gtk/gtk.h>
-
-G_DECLARE_FINAL_TYPE(MyApplication,
-                     my_application,
-                     MY,
-                     APPLICATION,
-                     GtkApplication)
-
-/**
- * my_application_new:
- *
- * Creates a new Flutter-based application.
- *
- * Returns: a new #MyApplication.
- */
-MyApplication* my_application_new();
-
-#endif  // FLUTTER_MY_APPLICATION_H_
+#ifndef FLUTTER_MY_APPLICATION_H_
+#define FLUTTER_MY_APPLICATION_H_
+
+#include <gtk/gtk.h>
+
+G_DECLARE_FINAL_TYPE(MyApplication,
+                     my_application,
+                     MY,
+                     APPLICATION,
+                     GtkApplication)
+
+/**
+ * my_application_new:
+ *
+ * Creates a new Flutter-based application.
+ *
+ * Returns: a new #MyApplication.
+ */
+MyApplication* my_application_new();
+
+#endif  // FLUTTER_MY_APPLICATION_H_