Fixed marks grouping and coloring for simultaneous multi marks definition

[ahlinc]

This PR fixes an issue with multiple simultaneous mark groups defined. The issue exists on a latest Kitty version and on top of the master branch. If I try to define several marks simultaneously in any available approach I got a text colored just by one color and that color just corresponds to a first mark group in the making definition.

Steps to reproduce:

1. echo -e 'WARN\nERROR\nFAIL'
2. kitty @ create-marker regex 1 FAIL 2 ERR 3 WARN

All three words should have different colors but all of them just colored as the FAIL word by the color of the first group in the applied marking definition.

Bellow screenshots demonstrate the issue:

With the PR fix:

P.S: And thanks for the great project! 🚀

[ahlinc]

Super fast merge 🚀 😺 Thanks!