[code-reflection] RFR: Update jdk version in opgen project [v2]

[Ana Maria Mihalceanu]

> This PR fixes the JDK version in `opgen` project. 
> As Babylon is based now on JDK 26, the project setup should be based on JDK 26.
> 
> In a terminal window, running `mvn clean verify` from `cr-examples/onnx/pom.xml` failed with  
> 
> 
> [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.11.0:compile (default-compile) on project onnx-opgen: Compilation failure
> [ERROR] invalid source release 25 with --enable-preview
> [ERROR]   (preview language features are only supported for release 26)

Ana Maria Mihalceanu has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  Allow arbritrary text to be injected using annotations

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Changes: https://git.openjdk.org/babylon/pull/634/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=634&range=01
  Stats: 23 lines in 5 files changed: 12 ins; 2 del; 9 mod
  Patch: https://git.openjdk.org/babylon/pull/634.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/634/head:pull/634

PR: https://git.openjdk.org/babylon/pull/634