fix: color of text-muted css selector

[ert78gb]

closes: #2149

Summary:

• tried to follow the bootstrap 5 dark style. Because in the future we would like to switch to BS dark mode instead of custom dark mode.
• use text-body-secondary as successor text-muted
• --bs-secondary-color use the $secondary color in dark mode

Also fixing the keymap selector of the popover when the list item keymap equal to the currently selected keymap.

Before:

After: