Add clang-format pre-commit hook about manifold

[pca006132]

Maybe we should add a .clang-format file with

BasedOnStyle: Google

and add a github action to check for formatting on PRs? Error when the source files are not formatted properly.

iirc we cannot enforce pre-commit hook and using GitHub action for formatting commit seems like an overkill and may make the history messy.

[elalish]

Sure, that sounds good.

[fire]

Block the merge until all the pre-commit hooks pass. Add an action to compile. Add an action to test clang format and abort if has changes.