Rename # vndk tag to # llndk

The APIs that are tagged with # vndk are actually for LLNDK libraries.
Although LLNDK is part of VNDK, calling those APIs 'vndk' has given
users a wrong perception that the APIs don't need to be kept stable
because that's the norm for most of the VNDK libraries that are not
LLNDK.

In order to eliminate the misunderstanding, rename the tag to 'llndk' so
that people introducing new such API will realize what they are signing
themselves up for.

Bug: 143765505
Test: m
Change-Id: I7ae77e232ec25cbe7afd98d1b68fc7a7fcf9bdfd

native/android/libandroid_net.map.txt

@@ -1,15 +1,19 @@
-# They are also all available to vendor code.
+# The following symbols marked with # llndk are available to vendor code.
+# Unlike other VNDK libraries where keeping backwards compatibility is required
+# only within a platform release, these symbols need much longer suppport
+# because the same LLNDK library serves for both system and vendor partition
+# which might be a few years old.
 LIBANDROID_NET {
   global:
     # These functions have been part of the NDK since API 24.
-    android_getaddrinfofornetwork; # vndk
-    android_setsocknetwork; # vndk
-    android_setprocnetwork; # vndk
+    android_getaddrinfofornetwork; # llndk
+    android_setsocknetwork; # llndk
+    android_setprocnetwork; # llndk
     # These functions have been part of the NDK since API 29.
-    android_res_cancel; # vndk
-    android_res_nquery; # vndk
-    android_res_nresult; # vndk
-    android_res_nsend; # vndk
+    android_res_cancel; # llndk
+    android_res_nquery; # llndk
+    android_res_nresult; # llndk
+    android_res_nsend; # llndk
   local:
     *;
 };