fix: not running other autocmd

[vunhatchuong]

Problem:

Things like treesitter and lsp don't work correctly when using the plugin.

Notice my buffer has no treesitter highlight and bottom right says "No servers", you can run LspInfo to check that no clients are attached.

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Solution:

Uses nested = true for the BufNewFile autocmd.

I honestly don’t fully understand why this works, which explains why my commit message description is so vague.

I copy what lewis6991/fileline.nvim does which works since it has the same workflow.