Color: Removal of nyan-mode local copy

[tonyfloatersu]

Hi there,

I opened up this PR as I encountered the same issue in #12946, that
nyan-mode won't show up under doom-modeline setting. The solution
here seems to be taking advantage of the nyan-mode on MELPA, which
is essentially the one-line change in colors/packages.el. If we go down
this way, then we can take away the local copy of nyan-mode altogether.

I also checked around and removed some text mentioning nyan-mode,
but I am unsure if we are allowed to do so (for example in COPYRIGHT).
I would refer the decision up to the code owner.

Thanks in advance for reviewing bandwidth.

Hang

[smile13241324]

I am not sure that's that easy, I dimly remember that there is an open pr with improvements to the nyan cat animation from sylable which never has been merged.

I think we need to either get this merged or do a fork ourselves.

Anyway I am going to merge it for now for when it stopped working entirely for one theme its more important than the improved graphics but we should still try to get these back in time

[tonyfloatersu]

Oh thanks for the context of nyan cat animation improvement, I was totally unaware of that... but thanks for taking a look and thanks for merging