fix: don't clear rules after closing floating win (#342)

When `BufDelete` is triggered after closing a floating window
such as one from `vim-floaterm`, the `bufnr` the event gets is that
of the file you're editing, not the buffer for the terminal, which is
causing this autocommand to clear the rules for the current file.

Making sure the buffer we're clearing rules for isn't the buffer we're
currently on fixes the issue for me, and seems to make sense because I
would imagine the buffer we're currently looking at isn't the buffer
that we just deleted and thus triggered a `BufDelete` event.

lua/nvim-autopairs.lua

@@ -62,7 +62,11 @@ M.setup = function(opt)
     api.nvim_create_autocmd('BufDelete', {
         group = group, pattern = '*',
         callback = function(data)
-            M.set_buf_rule(nil, tonumber(data.buf) or 0)
+            local cur = api.nvim_get_current_buf()
+            local bufnr = tonumber(data.buf) or 0
+            if bufnr ~= cur then
+                M.set_buf_rule(nil, bufnr)
+            end
         end,
     })
     api.nvim_create_autocmd('FileType', {