RFR: 8313408: Use SVG for BoxLayout example

[Phil Race]

On Sat, 5 Aug 2023 19:13:20 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> Replace the GIF image of `BoxLayout` example with an SVG one which renders crisp on all the displays, including High DPI ones.
> 
> Compare the images:
> 
>   * [`BoxLayout`](https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/javax/swing/BoxLayout.html#class-description), Java 17, with GIF image;
>   * [`BoxLayout`](https://cr.openjdk.org/~aivanov/8313408/api/java.desktop/javax/swing/BoxLayout.html#class-description) with SVG image.
> 
> (The updated version lacks CSS and JS from the javadoc tool; there are only two files `BoxLayout.html` and `BoxLayout-1.svg`.)

Marked as reviewed by prr (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/15169#pullrequestreview-1583526460