Fix issue with minus and fraction. about nabla.nvim

[nyngwang]

@jbyuki I believe "adding spaces around operators" is still something that needs to be considered.

[jbyuki]

I have added spaces around most operators. I might have not thought of some corners cases so feel free to open an issue for that.

[nyngwang]

I will die for pixel font. Anyway, I meant the font is open-source and I like it, so can't change it.

Still thanks for your help!

[jbyuki]

Coloring should make this readable.

[nyngwang]

@jbyuki I think these two are the only things to be fixed: partial derivative and large parentheses for matrices and nested expressions. Tested against 3b0a1bb. For references:

• $\frac{\partial x}{\partial f(x)}\, +\, \frac{\partial y}{\partial f(y)}\, =\, 2$
• $\begin{pmatrix} 1 & 5 \\ 3 & 4 \end{pmatrix}$

[jbyuki]

You need to pick another font. It will fix it.