mime_essence empty with some files

[pbosab]

Hello,

started using https://github.com/Junker/nuke.xplr and noticed a strange behavior, some simple plain/text files were not recognized and didn't met the regex match.

the file was named "note" made with vim and without extension.

function open of nuke.xplr/init.lua:

local function open(ctx)
    local node = ctx.focused_node
    local node_mime = node.mime_essence

when selecting the "note" file, node_mime is empty.

❯ file -i note
note: text/plain; charset=us-ascii

xplr version: 0.21.1

[sayanarijit]

We can probably improve mime detection, but need to be careful about the performance impact. The current library we're using may not be perfect, but is good enough performance-wise. For usecases, where a more precise mime detection is required, it's recommended to use the file command instead of depending on node.mime_essence.