Improve spellcheck script to allow for projects to specify additional sources

[adeljo-amd]

This PR contains the following update:

• Added config to spell-check C++ files in .spellcheck.yaml
• Added a file .spellcheck.local.yaml that can be used as a reference for other projects when they want to specify additional sources
• Added a python script docs/yaml_merger.py to merge any project's .spellcheck.local.yaml with the main .spellcheck.yaml in this repository. The script simply checks the nodes name and source and ensures they match before merging the additional sources (node depth must match too). Anything else is ignored.

[adeljo-amd]

Here is a test action in the HIP repository that shows the spellcheck run https://github.com/ROCm/HIP/actions/runs/12868847369/job/35990222242

And in the ROCm repository
https://github.com/ROCm/ROCm/actions/runs/12868894294/job/35992068272

[samjwu]

I think this may belong to ci: instead of feat: since it's affecting workflow files (for the commitizen commit message)

is there a need to release a new version for this?

[adeljo-amd]

I think this may belong to ci: instead of feat: since it's affecting workflow files (for the commitizen commit message)

is there a need to release a new version for this?

Thanks for pointing that out, squashed and adjusted the commit message.

Spoke to @neon60 about the need to release and he says no.