Update language to comply with Android’s inclusive language guidance

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


BUG=161896447

Change-Id: I93461b526cd69f9ebfa876edc6445df29746968e
diff --git a/contexthub/1.0/default/Contexthub.cpp b/contexthub/1.0/default/Contexthub.cpp
index 5f83a22..a08c520 100644
--- a/contexthub/1.0/default/Contexthub.cpp
+++ b/contexthub/1.0/default/Contexthub.cpp
@@ -155,10 +155,10 @@
         .message = static_cast<const uint8_t *>(msg.msg.data()),
     };
 
-    // Use a dummy to prevent send_message with empty message from failing prematurely
-    static uint8_t dummy;
+    // Use a placeholder to prevent send_message with empty message from failing prematurely
+    static uint8_t placeholder;
     if (txMsg.message_len == 0 && txMsg.message == nullptr) {
-        txMsg.message = &dummy;
+        txMsg.message = &placeholder;
     }
 
     ALOGI("Sending msg of type %" PRIu32 ", size %" PRIu32 " to app 0x%" PRIx64,
@@ -255,7 +255,7 @@
 
     memcpy(rsp, msg, sizeof(*rsp));
 
-    // No sanity checks on return values
+    // No validations on return values
     return true;
 }