Hard to see things with the Apprentice colorscheme

[gfixler]

I'm using romainl's Apprentice colorscheme, but the text in the popup is hard to see.

[pechorin]

Now you can customize any color via:

let g:any_jump_colors = {
      \"plain_text":         "Comment",
      \"preview":            "Comment",
      \"preview_keyword":    "Operator",
      \"heading_text":       "Function",
      \"heading_keyword":    "Identifier",
      \"group_text":         "Comment",
      \"group_name":         "Function",
      \"more_button":        "Operator",
      \"more_explain":       "Comment",
      \"result_line_number": "Comment",
      \"result_text":        "Statement",
      \"result_path":        "String",
      \"help":               "Comment"
      \}

Added in 330b535