Docs: Fix Terminology in Resource / Labware Comparison (#716)

Author: BioCam

docs/resources/index.md

@@ -114,7 +114,7 @@ PLR's `Resource` subclasses in the inheritance tree are:
     However, in our discussions, it became evident that the term "labware" has different meanings to different stakeholders
     (e.g., "A plate is clearly labware, but is a liquid handler or a plate reader labware?").
     As a result, PLR avoids the ambiguous term "labware".</p>
-    <p><u>Every physical item (describable via its <code>item_x</code>, <code>item_y</code>, <code>item_z</code>) is a "resource"</u>.</p>
+    <p><u>Every physical item (describable by its physical dimensions <code>size_x</code>, <code>size_y</code>, <code>size_z</code>) is a `Resource`</u>.</p>
 </details>
 
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