[jfx25u] RFR: 8304008: Update README.md and CONTRIBUTING.md for jfx update repos

Tue Jul 22 06:42:32 UTC 2025

On Mon, 21 Jul 2025 21:00:57 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> This is a copy of the jfx24u README and CONTRIBUTING docs, changing 24 to 25.

The result of the PR looks very similar to the README.md and CONTRIBUTING.md in jfx21u, as expected.

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Marked as reviewed by jvos (Reviewer).

PR Review: https://git.openjdk.org/jfx25u/pull/2#pullrequestreview-3041371894