Make aapt2 terminology more inclusive

Update language to comply with Android's inclusive language guidance

See https://source.android.com/setup/contribute/respectful-code
for reference

Bug: 162364131
Bug: 162536543
Test: aapt2_tests
Change-Id: I4eef925d6319b40a395fc8d59a3f2912a02ca03b
diff --git a/tools/aapt2/ResourceParser.cpp b/tools/aapt2/ResourceParser.cpp
index 931a14b..3d9be59 100644
--- a/tools/aapt2/ResourceParser.cpp
+++ b/tools/aapt2/ResourceParser.cpp
@@ -342,7 +342,7 @@
     }
   }
 
-  // Sanity check to make sure we processed all the nodes.
+  // Validity check to make sure we processed all the nodes.
   CHECK(node_stack.size() == 1u);
   CHECK(node_stack.back() == &root);