feature(image): option to keep inline images in insert mode

[paperbenni]

Did you check the docs?

• I have read all the snacks.nvim docs

Is your feature request related to a problem? Please describe.

All inline image rendering gets hidden as soon as insert mode is entered, even if it is not on the line which is being edited.
If I am writing a math expression which relates to a different expression, being able to view the other expression in a rendered format while editing the current one is a lot nicer than looking at the latex source.
Hiding all images while in insert mode also causes a lot of visual changes across the entire screen on every mode switch.

Describe the solution you'd like

As far as I can tell, just removing the mode check from this line

6ea4fa7#diff-ae3c0826707693cb017fb36df5071e7d6a138e52ccf71ea859b9aa1a9b8b78b7R40

achieves the desired behavior (at least in insert mode). Introducing an option to disable or customize the mode check would be nice.

The current behavior also differs from most other conceal features, which only get hidden when being edited or selected, so maybe even changing the default would be a good idea.

In visual mode, hiding all images which are part of the selection but keeping others would also be nice, but I am unsure how much more complicated that would be to implement.

Describe alternatives you've considered

Latex concealment which support partial concealment using other plugins like markview is possible, but glitchy in combination with snacks, looks worse and requires parsing the latex twice. That said, I would definitely appreciate concealing greek letters with unicode so the line looks shorter while editing.

I am sorry for how long this issue is, hopefully some of the ideas are helpful :)

Additional context

No response