Struct doc suggestions (#111)

* Update native-buffer/malloc docs to more directly pointer to
resource-type docs.

* Add 2-arity call to `dt-struct/map->struct`.

src/tech/v3/datatype/native_buffer.clj

@@ -867,7 +867,7 @@
 
   Options:
 
-  * `:resource-type` - defaults to `:gc` - maps to `:track-type` in `tech.v3.resource`
+  * `:resource-type` - defaults to `:gc` - maps to `:track-type` in `tech.v3.resource/track`
      but can also be set to nil in which case the data is not tracked this library will
      not clean it up.
   * `:uninitialized?` - do not initialize to zero.  Use for perf in very very rare cases.

src/tech/v3/datatype/struct.clj

@@ -461,9 +461,11 @@ user> *2
 
 
 (defn map->struct
-  [dtype data track-type]
-  (map->struct! data (new-struct dtype {:container-type :native-heap
-                                        :resource-type track-type})))
+  ([dtype data]
+   (map->struct dtype data :gc))
+  ([dtype data track-type]
+   (map->struct! data (new-struct dtype {:container-type :native-heap
+                                         :resource-type track-type}))))
 
 
 (declare inplace-new-array-of-structs)