add support for topiary

[georgeharker]

Topiary is a tree-sitter based formatter.

I recently opened a PR there to add zsh support.

[stevearc]

Instead of having a single override value, I think it would be better to expose the ft_to_language map on the options like we do for the injected formatter

conform.nvim/lua/conform/formatters/injected.lua

Lines 185 to 187 in 5420c4b

	lang_to_ft = {
	bash = "sh",
	},

That way it's easy for a user to override a particular language opt without clobbering all the others.

We can also fall back to using the raw vim filetype if there is no entry, and that will allow us to remove all the entries where the values are the same. I know that means the condition won't work anymore, but I don't think the condition is that important.

[georgeharker]

I'm a bit stalled with the topiary folks right now on zsh integration so this is a bit reduced in priority. Can fix as suggested or reopen when / if Zsh integration is done.