fix: get_range shim for playground

[dtomvan]

This PR adds more shims in the nvim-treesitter.compat module and reroutes every
occurrence of the old function calls to the new ones, to comply with the
breaking neovim/neovim@cbbf8bd.

I have made this pull request to quickly solve deprecation messages for those on
neovim nightly, such as in nvim-treesitter/playground#120.

[dtomvan]

Oops, changing the vim.treesitter.get_node back to vim.treesitter.get_node_at_pos because it hasn't existed so far on stable appearantely.

[max397574]

you should just add if statements to check if the new functions exists and if so you should use them I guess

[dtomvan]

you should just add if statements to check if the new functions exists

@max397574 that's the point of the compat module, maybe this could be a shim too but the only use were in the tests and I won't touch those (even though I did in the first pass of this tiny contribution).