Clarifiy ADR states in documentation

Bug: 167930284
Test: n/a
Change-Id: Ifa0633b2cfa7bb80e32d2c68d70992bc1b0c5461
diff --git a/gnss/1.1/IGnssMeasurementCallback.hal b/gnss/1.1/IGnssMeasurementCallback.hal
index 5a60a56..36841ee 100644
--- a/gnss/1.1/IGnssMeasurementCallback.hal
+++ b/gnss/1.1/IGnssMeasurementCallback.hal
@@ -20,8 +20,18 @@
 
 /** The callback interface to report measurements from the HAL. */
 interface IGnssMeasurementCallback extends @1.0::IGnssMeasurementCallback {
-    /**
+     /**
      * Flags indicating the Accumulated Delta Range's states.
+     *
+     * See the table below for a detailed interpretation of each state. This is
+     * a continuation of the table from 1.1/IGnssMeasurementCallback.hal.
+     *
+     * +---------------------+-------------------+-----------------------------+
+     * | ADR_STATE           | Time of relevance | Interpretation              |
+     * +---------------------+-------------------+-----------------------------+
+     * | HALF_CYCLE_RESOLVED | ADR(t)            | Half cycle ambiguity is     |
+     * |                     |                   | resolved at time t.         |
+     * +---------------------+-------------------+-----------------------------+
      */
     enum GnssAccumulatedDeltaRangeState
             : @1.0::IGnssMeasurementCallback.GnssAccumulatedDeltaRangeState {