perf(icon): update default icon for unknown filetype (#361)

* perf(icon): update default icon for unknown filetype

* docs(config): update icons

* perf(stylua): set indent width=2

* chore(pr): format with stylua

* docs(keymaps): add FzfxGStatus mapping, reduce useless variants

* revert

* chore(pr): format with stylua

* revert

* revert

---------

Co-authored-by: linrongbin16 <linrongbin16@users.noreply.github.com>