Remove depwarn for X11 color names with spaces

[kimikage]

This also removes color(::AbstractString) and depreates parse(::Type, ::Colorant).

cf. #431 (comment)

[codecov]

Codecov Report

Merging #462 (5827351) into master (65c4e5a) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #462   +/-   ##
=======================================
  Coverage   91.21%   91.21%           
=======================================
  Files           9        9           
  Lines         956      956           
=======================================
  Hits          872      872           
  Misses         84       84           

Impacted Files	Coverage Δ
src/parse.jl	93.50% <100.00%> (ø)

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[kimikage]

Test for X11 color names with spaces.

with_sp = [
    "alice blue"
    "antique white"
    "blanched almond"
    "blue violet"
    "cadet blue"
    "cornflower blue"
    "dark blue"
    "dark cyan"
    "dark goldenrod"
    "dark gray"
    "dark green"
    "dark grey"
    "dark khaki"
    "dark magenta"
    "dark olive green"
    "dark orange"
    "dark orchid"
    "dark red"
    "dark salmon"
    "dark sea green"
    "dark slate blue"
    "dark slate gray"
    "dark slate grey"
    "dark turquoise"
    "dark violet"
    "deep pink"
    "deep sky blue"
    "dim gray"
    "dim grey"
    "dodger blue"
    "floral white"
    "forest green"
    "ghost white"
    "green yellow"
    "hot pink"
    "indian red"
    "lavender blush"
    "lawn green"
    "lemon chiffon"
    "light blue"
    "light coral"
    "light cyan"
    "light goldenrod"
    "light goldenrod yellow"
    "light gray"
    "light green"
    "light grey"
    "light pink"
    "light salmon"
    "light sea green"
    "light sky blue"
    "light slate blue"
    "light slate gray"
    "light slate grey"
    "light steel blue"
    "light yellow"
    "lime green"
    "medium aquamarine"
    "medium blue"
    "medium orchid"
    "medium purple"
    "medium sea green"
    "medium slate blue"
    "medium spring green"
    "medium turquoise"
    "medium violet red"
    "midnight blue"
    "mint cream"
    "misty rose"
    "navajo white"
    "navy blue"
    "old lace"
    "olive drab"
    "orange red"
    "pale goldenrod"
    "pale green"
    "pale turquoise"
    "pale violet red"
    "papaya whip"
    "peach puff"
    "powder blue"
    "rebecca purple"
    "rosy brown"
    "royal blue"
    "saddle brown"
    "sandy brown"
    "sea green"
    "sky blue"
    "slate blue"
    "slate gray"
    "slate grey"
    "spring green"
    "steel blue"
    "violet red"
    "white smoke"
    "yellow green"];

parse.(Color, with_sp);