The root_markers field can now contain a table of tables (as of
https://github.com/neovim/neovim/pull/33485) and :checkhealth will show
an error in that case since Lua cannot concatenate a table of tables.
Ensure that tables contain strings before concatenating and if not, fall
back to using vim.inspect().
(cherry picked from commit 5ad01184f3)
Co-authored-by: Gregory Anders <greg@gpanders.com>
d185057bc7