Kanagawa: fix palette and attempt at a markdown compromise

[luetage]

Our current palette curiously doubles sumiInk2 and sumiInk4, which is the same color. I took the original palette from Kanagawa and added the color explanations from its readme. Additionally I commented out all colors which are not in use, for a better overview. This operation didn’t change the highlighting, but I had to do a few fixes for the changed sumiInk numbering.

Additionally I’m rather unhappy with the current markdown highlighting, because I do quite a bit of note taking and the original Kanagawa doesn’t care about it at all. I installed nvim again to check the theme out in its native environment. First of all we have one “error”, springViolet1 instead of oniviolet2 for quotes. This was my own mistake from an earlier pull request. The link color is neither good with or without treesitter on nvim, I suggest to use lightBlue instead—URLs deserve their very own color. Two more heading colors don’t hurt; and lists are almost invisible right now, I changed them to sakuraPink. It’s all a matter of taste of course, but in my opinion it becomes more readable and easier to distinguish.

@zetashift

[zetashift]

Am I right in seeing that header 3/4/5 are all the same color? If so could you add these colors as well. I'm not sure which colors, because I kinda like contrast between the headers, as it makes outlining easier.

lightBlue for URLs looks good to me.

[luetage]

We used to have that ☛ #6085
In practice I’ve never seen heading 5 and 6 in use though, maybe 4 different colors? This would add one. But we can of course theme it completely too.

[zetashift]

We used to have that ☛ #6085 In practice I’ve never seen heading 5 and 6 in use though, maybe 4 different colors? This would add one. But we can of course theme it completely too.

4 different colors sounds like a fine tradeoff!

[zetashift]

Thank you! :D