[clang] Treat ipynb as json (PR #135137)

[Björn Schäpers via cfe-commits]

https://github.com/HazardyKnusperkeks commented:

I think you should also update:
* `git-clang-format`
* The help text in `ClangFormat.cpp`
* Run `clang/docs/tools/dump_format_help.py`
* `clang-format-diff.py`

https://github.com/llvm/llvm-project/pull/135137