fix: replace deprecated table methods for neovim v0.10

[skoch13]

Credits go to sindrets/diffview.nvim#489

Fixes #1689

[mikesmithgh]

FYI @skoch13 sindrets/diffview.nvim#489 (comment)

I also do not see the error on the latest version of nvim nightly.

I made a change to sindrets/diffview.nvim#489 to add the depth of math.huge to the flatten function that should be updated in the PR.

[skoch13]

@mikesmithgh thank you, I did mention that in the issue here #1689 (comment)

I'll update the PR accordingly, thank you

[baodrate]

I'm also deprecating these functions in my code and using this as a reference. am I missing something here? or should this be:

Suggested change

	---@return function
	function M.islist()
	return vim.fn.has "nvim-0.10" == 1 and vim.islist or vim.tbl_islist ---@diagnostic disable-line: deprecated
	end
	---@param t? table
	---@return boolean `true` if list-like table, else `false`.
	function M.islist(t)
	return (vim.fn.has("nvim-0.10") == 1 and vim.islist or vim.tbl_islist)(t) ---@diagnostic disable-line: deprecated
	end

or maybe just:

Suggested change

	---@return function
	function M.islist()
	return vim.fn.has "nvim-0.10" == 1 and vim.islist or vim.tbl_islist ---@diagnostic disable-line: deprecated
	end
	M.islist = vim.fn.has("nvim-0.10") == 1 and vim.islist or vim.tbl_islist ---@diagnostic disable-line: deprecated

[williamboman]

Thanks for the PR! It seems like Neovim nightly temporarily broke due to the introduction of some calls that are not allowed in :h vim.in_fast_event() (in which Mason executes quite a lot of code). It seems like that issue was fixed in the next nightly release.

There are some issues with these changes currently - current usage of flatten expects support for keyed tables, the islist() function seems to return the function it's meant to call, and the introduction of functions in the utils.lua is a bit misplaced (this is a util module local to the mason-core.installer.registry module).

Thanks for brining it to my attention, I'll close this PR and open another one to replace these usages!