Searching the entire repo for a directory named "contrib" causes failure
if there happens to be another subdirectory with the name "contrib".
Instead, point directly to the correct contrib directory.
Problem:
No easy way to find files under certain directories (ex: grab all files under
`test/`) or exclude the content of certain paths (ex. `build/`, `.git/`)
Solution:
Pass the full `path` as an arg to the predicate.
Extend the capabilities of is_os to detect more platforms such as
freebsd and openbsd. Also remove `iswin()` helper function as it can be
replaced by `is_os("win")`.
Makes it possible to use `vim.fs.find` to find files where only a
substring is known.
This is useful for `vim.lsp.start` to get the `root_dir` for languages
where the project-file is only known by its extension, not by the full
name.
For example in .NET projects there is usually a `<projectname>.csproj`
file in the project root.
Example:
vim.fs.find(function(x) return vim.endswith(x, '.csproj') end, { upward = true })
