#5537 Doc: Document new function for css-color (accompanying x11-color)

new function introduced in issue #5524

commit:
author Urs Liska <ul@openlilylib.org> Mon, 15 Jul 2019 21:38:16 +0100 (21:38 +0100) committer James Lowe <pkx166h@runbox.com> Mon, 15 Jul 2019 21:40:41 +0100 (21:40 +0100) commit 7ecc24c5e8bfc13b58abb02154eaadfda2f38307

X11 and CSS colors are now
independently accessible
through #(x11-color <name>)
or #(css-color <name>).</name></name>

Both color models are now
completely case insensitive
(as they should be), and
spaces are simply stripped
from the argument.

That way all combinations of
symbols/strings, CamelCased
or lowercase etc. are accepted.

If no color is found by
the requested name a warning
is issued (unfortunately
that can't be an input warning).

[Anonymous]

Doc: NR - Doc CSS colour support

Issue 5537
Document support for CSS colour.

This function was added in
commit 7ecc24c5

Includes minor layout fixes
and edits to incorporate both
X11 and CSS support in the same
NR section and appendixes.

https://codereview.appspot.com/551270043

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

Typos from Werner L.

https://codereview.appspot.com/551270043

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

Removal of i.e. and e.g. (and so ugly commas)

https://codereview.appspot.com/551270043