Adding "@defgroup" DOxygen tag to AMidi

Bug: 122672555
Test: Build DOxygen docs
Change-Id: I2022facfab601da63a64682188d31821b33bb8cc

media/native/midi/include/Doxyfile

@@ -790,7 +790,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = "midi.h"
+INPUT                  = "amidi/AMidi.h"
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

media/native/midi/include/amidi/AMidi.h

@@ -13,6 +13,14 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+/**
+ * @addtogroup Midi
+ * @{
+ */
+
+/**
+ * @file AMidi.h
+ */
 
 #ifndef ANDROID_MEDIA_AMIDI_H_
 #define ANDROID_MEDIA_AMIDI_H_
@@ -244,3 +252,6 @@ void AMIDI_API AMidiInputPort_close(const AMidiInputPort *inputPort) __INTRODUCE
 #endif
 
 #endif /* ANDROID_MEDIA_AMIDI_H_ */
+/**
+@}
+*/