Custom icon rule behavior

[Valombreuse]

Hi Florian,

I'm trying to play with the rules and figure out how it works to improve my vault and ultimately help you write this documentation.

Describe the bug
Some webp icons fall into the rule and some don't.

rule :
.webp

Also this is not an issue but I'm trying to figure out how to have a rule that apply to multiple file formats.
So far I tried separating the file formats with :
,
;

without success, Maybe it's not possible. If not that would be cool to be able to simple separating the file formats with comas.