🧑‍💻 Fix button stories/documentation page

The <Story of=...> was deprecated earlier, which caused the buttons
not to be properly displayed any longer.

src/components/Button/OFButton.mdx

@@ -16,33 +16,25 @@ aria attribute instead.
 More information on the Utrecht buttons can be found
 [here](https://nl-design-system.github.io/themes/?path=/docs/button--gemeente-utrecht).
 
-<Canvas>
-  <Story of={OFButtonStories.UtrechtDefault} />
-  <Story of={OFButtonStories.UtrechtPrimary} />
-  <Story of={OFButtonStories.UtrechtSecondary} />
-  <Story of={OFButtonStories.UtrechtDanger} />
-</Canvas>
+<Canvas of={OFButtonStories.UtrechtDefault} />
+<Canvas of={OFButtonStories.UtrechtPrimary} />
+<Canvas of={OFButtonStories.UtrechtSecondary} />
+<Canvas of={OFButtonStories.UtrechtDanger} />
 
 ### Links that look like buttons
 
-<Canvas>
-  <Story of={OFButtonStories.UtrechtLinkLooksLikeDefaultButton} />
-  <Story of={OFButtonStories.UtrechtLinkLooksLikePrimaryButton} />
-  <Story of={OFButtonStories.UtrechtLinkLooksLikeSecondaryButton} />
-</Canvas>
+<Canvas of={OFButtonStories.UtrechtLinkLooksLikeDefaultButton} />
+<Canvas of={OFButtonStories.UtrechtLinkLooksLikePrimaryButton} />
+<Canvas of={OFButtonStories.UtrechtLinkLooksLikeSecondaryButton} />
 
 ### Button that looks like a link
 
-<Canvas>
-  <Story of={OFButtonStories.UtrechtButtonLooksLikeLink} />
-</Canvas>
+<Canvas of={OFButtonStories.UtrechtButtonLooksLikeLink} />
 
 ## Icon buttons
 
-<Canvas>
-  <Story of={OFButtonStories.UtrechtIconButton} />
-  <Story of={OFButtonStories.UtrechtIconButtonDanger} />
-</Canvas>
+<Canvas of={OFButtonStories.UtrechtIconButton} />
+<Canvas of={OFButtonStories.UtrechtIconButtonDanger} />
 
 ## Disabled state