Better exception for failed StructMapper deserialization

Author: crc-32

src/commonMain/kotlin/io/rebble/libpebblecommon/structmapper/StructMapper.kt

@@ -35,8 +35,13 @@ class StructMapper: Mappable {
     }
 
     override fun fromBytes(bytes: DataBuffer) {
-        getStruct().forEach {
-            it.fromBytes(bytes)
+        getStruct().forEachIndexed { i: Int, mappable: Mappable ->
+            try {
+                mappable.fromBytes(bytes)
+            }catch (e: Exception) {
+                throw PacketDecodeException("Unable to deserialize mappable ${mappable::class.simpleName} at index $i (${mappable})", e)
+            }
+
         }
     }