vim: Lighten font in MacVim
vim: Lighten font in MacVim

I'm using "Light" in iTerm, but iTerm renders it thinner than MacVim
does because I have the "Use thin strokes for anti-aliased text" setting
set to "On Retina displays".

Using "ExtraLight" for `'guifont'` brings MacVim's rendering a little
closer to iTerm's.

(Why am I using MacVim? Just wanted to do some speed comparisons with
the terminal, as I have been pretty frustrated by the slow rendering
there of late.)

Note that due to https://github.com/macvim-dev/macvim/issues/371 MacVim
only "sees" these user-installed fonts when launched by double-clicking
the application icon; running `mvim` (even outside tmux) means it can't
see the fonts. Haven't bothered moving them outside of `~/Library/Fonts`
to see if that makes a difference or not, and I don't think I'll use
this often enough to warrant doing a `reattach-to-user-namespace` hack,
although it's pretty easy to do so so I just might do it.

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent