Fix lsp provider when lsp does not return an array

Hey, hello, I was using Trouble with rescript-language-server and I was having issues using lsp provider, it wasn't working, so when I debbuged the issue I found that rescript-language-server was responding the follow to the lsp_buf_request function:

{
  range = {
    ["end"] = {
      character = 23,
      line = 1
    },
    start = {
      character = 6,
      line = 1
    }
  },
  uri = "file:///Users/matheus.ashton/dev/pessoal/rsus/src/Transactions/TransactionsPage.res"
}

And in here the evaluation of #result == 0 is true, because the length operator works differently if the table has not an array part: https://stackoverflow.com/a/23591039

So it understands that there is no result at all, but in fact it is just not formatted right.

So I added a vim.tbl_isempty inside each test in order to check if it's indeed has no result or if it just don't have and array part in the table.

This fixed the issue for me.

PS: Also, if you check this same case comparing the behavior of vim.lsp.buf.definition() it works normally.

folke / trouble.nvim

Fix lsp provider when lsp does not return an array #366