Add a new segment when extending a theme

[Sebi11]

Hi! First of all, thank you for the work on this amazing project!

Despite reading the doc of "extends", I cant help myself adding a new segment to an existing theme. Here is my custom theme right now:

{
  "$schema": "https://raw.githubusercontent.com/JanDeDobbeleer/oh-my-posh/main/themes/schema.json",
  "extends": "powerlevel10k_rainbow",
  "upgrade": {
    "notice": true
  },
  "blocks": [
    {
      "type": "prompt",
      "alignment": "left",
      "segments": [
        {
          "type": "os",
          "template": " {{ if .WSL }}WSL at {{ end }}{{.Icon}} {{ if .Env.CONTAINER_ID }} in \uED95  {{ .Env.CONTAINER_ID }}{{ end }} "
        },
        {
          "type": "path"
        },
        {
          "type": "git"
        },
        {
          "type": "text",
          "style": "plain",
          "foreground": "#3069de",
          "template": " Hello World "
        }
      ]
    }
  ]
}

Modifying the segment with "type": "os" is working fine, so I guess there's no issue with my extension.
I tried adding "index": 4 to the last segment, without success sadly.

For the record, here is the theme I'm extending: https://github.com/JanDeDobbeleer/oh-my-posh/blob/main/themes/powerlevel10k_rainbow.omp.json

Could you help me please?

[JanDeDobbeleer]

@Sebi11 this isn't supported, but I can make it work. Adding isn't an issue per se.

[JanDeDobbeleer]

Will be done with #6871

[Sebi11]

Wow, that's so great, congrats and thanks!