Add @defgroup for ADataSpace file

Bug: 148875303
Test: able to see ADataSpace in NDK API preview
Change-Id: I8914e6d84da2dff8b52e6375440e97f8f3f8ee98
diff --git a/libs/nativewindow/include/android/data_space.h b/libs/nativewindow/include/android/data_space.h
index a299488..0565f42 100644
--- a/libs/nativewindow/include/android/data_space.h
+++ b/libs/nativewindow/include/android/data_space.h
@@ -15,6 +15,13 @@
  */
 
 /**
+ * @defgroup ADataSpace Data Space
+ *
+ * ADataSpace describes how to interpret colors.
+ * @{
+ */
+
+/**
  * @file data_space.h
  */
 
@@ -517,3 +524,5 @@
 __END_DECLS
 
 #endif // ANDROID_DATA_SPACE_H
+
+/** @} */