Highlight link to Normal paints bg boxes in transparent floats

In Neovim colorscheme overrides, linking groups like @punctuation.bracket or @punctuation.delimiter to Normal copies Normal's background too. In a float whose NormalFloat is transparent (e.g. LSP hover), every bracket, ::, <> and -> then draws a dark bg box. Normal buffers hide it because their bg matches. Fix: link to a fg-only group instead (gruvbox.nvim: GruvboxFg1) or set {fg = ...} explicitly.