docs(general): add note about matrices being stored in arrays

YoYoGames/GameMaker-Bugs#2960

Manual/contents/GameMaker_Language/GML_Overview/Data_Types.htm

@@ -43,6 +43,7 @@ <h1><span data-field="title" data-format="default">Data Types</span></h1>
   <p><a class="dropspot" data-rhwidget="DropSpot" data-target="drop-down2" href="#">Arrays</a></p>
   <div class="droptext" data-targetname="drop-down2">
     <p class="dropspot"><label for="three">An array is a special data type that can be used to hold multiple values. You assign the array to a variable, and then &quot;fill in&quot; different indices of the array with values. This array can then be passed through to scripts and functions on a <a href="Values_And_References.htm#pass_by_value_and_pass_by_reference">pass-by-reference</a> basis, however should you modify the passed array, it will then become a copy of the original array and so will need to be returned back to the original variable for the array to be updated. For more information on arrays, please see: <a href="Arrays.htm">GML Overview - Arrays</a>.</label></p>
+    <p class="dropspot">Note that matrices are also stored in arrays. See <a data-xref="{title}" href="../GML_Reference/Maths_And_Numbers/Matrix_Functions/Matrix_Functions.htm">Matrix Functions</a> for more information.</p>
     <p class="dropspot"> </p>
   </div>
   <p><a class="dropspot" data-rhwidget="DropSpot" data-target="drop-down3" href="#">Structs</a></p>