Show module type in a module section of the Android-TARGET.mk

The first line of each section will be
```
include $(CLEAR_VARS)  # <module type>
...
```

Bug: 257037252
Test: treehugger
Change-Id: Iba586155b682fe4e1e5817d8397eda8f9d9c8789
diff --git a/apex/androidmk.go b/apex/androidmk.go
index 3373211..0fc971b 100644
--- a/apex/androidmk.go
+++ b/apex/androidmk.go
@@ -134,7 +134,7 @@
 			continue
 		}
 
-		fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
+		fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)  # apex.apexBundle.files")
 		if fi.moduleDir != "" {
 			fmt.Fprintln(w, "LOCAL_PATH :=", fi.moduleDir)
 		} else {
@@ -348,7 +348,7 @@
 
 			if apexType == flattenedApex {
 				// Only image APEXes can be flattened.
-				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
+				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)  # apex.apexBundle.flat")
 				fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
 				fmt.Fprintln(w, "LOCAL_MODULE :=", name+a.suffix)
 				data.Entries.WriteLicenseVariables(w)
@@ -356,7 +356,7 @@
 				fmt.Fprintln(w, "include $(BUILD_PHONY_PACKAGE)")
 
 			} else {
-				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
+				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)  # apex.apexBundle")
 				fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
 				fmt.Fprintln(w, "LOCAL_MODULE :=", name+a.suffix)
 				data.Entries.WriteLicenseVariables(w)