Improve normalisation of calc()-like functions

[RobinMalfait]

This PR improves the normalisation of calc() functions.

In CSS, functions such as calc() require spaces around the operators. However, when writing Tailwind CSS classes we can't really use spaces. There are 2 solutions to this problem:

1. You write a _ instead of a space, which we will convert to a space behind the scenes
2. You don't write any spaces or _ characters, and you let Tailwind inject the spaces for you

Typically, you would let Tailwind inject the spaces, but we didn't catch all cases. This PR improves that by introducing a mini-parser for handling spaces around operators.

Looking at the examples given in #11682, then the updated result would look like this:

Input	Before	After
calc((7-32)/(1400-782))	calc((7-32) / (1400 - 782))	calc((7 - 32) / (1400 - 782))
calc((7-3)/(1400-782))	calc((7 - 3) / (1400 - 782))	calc((7 - 3) / (1400 - 782))
calc((7-32)/(1400-782))	calc((7-32) / (1400 - 782))	calc((7 - 32) / (1400 - 782))
calc((70-3)/(1400-782))	calc((70 - 3) / (1400 - 782))	calc((70 - 3) / (1400 - 782))
calc((70-32)/(1400-782))	calc((70-32) / (1400 - 782))	calc((70 - 32) / (1400 - 782))
calc((704-3)/(1400-782))	calc((704 - 3) / (1400 - 782))	calc((704 - 3) / (1400 - 782))
calc((704-320))	calc((704 - 320))	calc((704 - 320))
calc((704-320)/1)	calc((704-320) / 1)	calc((704 - 320) / 1)
calc((704-320)/(1400-782))	calc((704-320) / (1400 - 782))	calc((704 - 320) / (1400 - 782))

Fixes: #11682

[mblode]

3.3.4 caused the following line to break.

Input:
pb-[max(12px,calc(2*env(safe-area-inset-bottom)))]

New output:
padding-bottom: max(12px,calc(2 * env(safe - area - inset - bottom)));

Old output:
padding-bottom: max(12px,calc(2 * env(safe-area-inset-bottom)));

[Ryan-Maughan]

Also having issues with 3.3.4. Seems to add spaces for 'min-content' within a minmax function which is invalid.

Input:
grid-cols-[minmax(min-content,_25%),1fr]

New output:
grid-template-columns: minmax(min - content,25%) 1fr

Old output:
grid-template-columns: minmax(min-content,25%) 1fr

[Serator]

Hey @RobinMalfait. I too have encountered the problems described above. Tailwind magic is great, but when it's clear and predictable. In this case, not only does this change add problems, it also diverges from regular CSS on an implicit level. Although adding _ adds pain, it's better than implicit magic.

[jokull]

Another data point where this breaks previously working classes:

Input: grid-cols-[max-content,minmax(max-content,0.5fr)]
Output: grid-template-columns: max-content minmax(max - content,0.5fr)

Note the spacing around the - sign.

[RobinMalfait]

Hey @mblode, @Ryan-Maughan, @Serator and @jokull

We introduced a regression here, but this should be fixed by #12283, and is available in the latest release (3.3.5). Sorry for the inconvenience!