Possible out of bounds string access in std/colors parseColor and isColor

[liquidev]

As in the title.

Example

import std/colors

echo "".isColor

https://play.nim-lang.org/#ix=2qp5

Current Output

/usercode/in.nim(3)      in
/playground/nim/lib/pure/colors.nim(475) isColor
/playground/nim/lib/system/fatal.nim(49) sysFatal
Error: unhandled exception: index out of bounds, the container is empty [IndexError]

Expected Output

false

Possible Solution

This should be very simple to fix.
https://github.com/nim-lang/Nim/blob/devel/lib/pure/colors.nim#L455
Simply add name.len > 0 to the if statement condition in parseColor and isColor.

Additional Information

❯ nim -v
Nim Compiler Version 1.2.0 [Linux: amd64]
Compiled at 2020-04-03
Copyright (c) 2006-2020 by Andreas Rumpf

active boot switches: -d:release

Checking the source code, this issue is still present on devel.