flex-grow and flex-shrink CSS properties are unit-less, but Emmet adds units anyway

[lunaneff]

For example:

fg1 -> flex-grow: 1px;
fsh1 -> flex-shrink: 1px;
fx1-2-3 -> flex: 1px 2px 3px;

But it should be:

fg1 -> flex-grow: 1;
fsh1 -> flex-shrink: 1;
fx1-2-3 -> flex: 1 2 3px;