`--math` AKA align strict math behavior with documentation.

[calvinjuarez]

Per a gitter discussion:

--math=(always|no-division|parens|strict|strict-legacy)
-m=...

always:

• height: (5px + 5px) + 2px; → height: 12px;
• width: 10px + 1; → width: 11px;
• width: (10px + 1); → width: 11px;
• font: 16 / 4; → font: 4;
• font: (16 / 4); → font: 4;

no-division:

• height: (5px + 5px) + 2px; → height: 12px;
• width: 10px + 1; → width: 11px;
• width: (10px + 1); → width: 11px;
• font: 16 / 4; → font: 16 / 4;
• font: (16 / 4); → font: 4;

parens AND strict:

• height: (5px + 5px) + 2px; → height: 10px + 2px;
• width: 10px + 1; → width: 10px + 1;
• width: (10px + 1); → width: 11px;
• font: 16 / 4; → font: 16 / 4;
• font: (16 / 4); → font: 4;

strict-legacy:

• height: (5px + 5px) + 2px; → height: (5px + 5px) + 2px;
• width: 10px + 1; → width: 10px + 1;
• width: (10px + 1); → width: 11px;
• font: 16 / 4; → font: 16 / 4;
• font: (16 / 4); → font: 4;

Some Questions to Consider:

What about calc()?

[matthew-dean]

@calvinjuarez I went with parens-all and parens-division - see PR - #3274

[matthew-dean]

Closing just so we can keep the discussion in one place (in PR)