Rename x and y to pcbX and pcbY in via.mdx (#297)

fix syntax to match reality :)

Author: raykholo

docs/elements/via.mdx

@@ -25,8 +25,8 @@ import CircuitPreview from "@site/src/components/CircuitPreview"
       toLayer="bottom"
       outerDiameter="0.8mm"
       holeDiameter="0.4mm"
-      x={10}
-      y={10}
+      pcbX={10}
+      pcbY={10}
     />
   )`}
 />
@@ -40,5 +40,5 @@ import CircuitPreview from "@site/src/components/CircuitPreview"
 | toLayer | string | "bottom" | Ending layer for the via |
 | holeDiameter | number \| string | "0.4mm" | Diameter of the plated hole |
 | outerDiameter | number \| string | "0.8mm" | Outer diameter of the copper annular ring |
-| x | number | 0 | PCB X position of the via |
-| y | number | 0 | PCB Y position of the via |
+| pcbX | number | 0 | PCB X position of the via |
+| pcbY | number | 0 | PCB Y position of the via |