message: doc: Change doxygen URL to doxygen.bitcoincore.org
  The bitcoin core doxygen documentation has moved to
  see
  bitcoin-core/bitcoincore.org#681
  (the old URL still works as a redirect)
diff: @@ -54,7 +54,7 @@ The Bitcoin repo's [root README](/README.md) contains relevant information on th
  - [Productivity Notes](productivity.md)
  - [Release Notes](release-notes.md)
  - [Release Process](release-process.md)
  -- [Source Code Documentation (External Link)](https://dev.visucore.com/bitcoin/doxygen/)
  +- [Source Code Documentation (External Link)](https://doxygen.bitcoincore.org/)
  - [Translation Process](translation_process.md)
  - [Translation Strings Policy](translation_strings_policy.md)
  - [JSON-RPC Interface](JSON-RPC-interface.md)
  