Fix UTF-8 offset in the STL regex pre-tokenizer fallback - #1136

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@a37ce9120846195fa4ece8f58b268e6043cb2f26, gradle/wrapper-validation-action@b5418f5a58f5fd2eb486dd7efb368fe7be7eae45. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/