Closes #4340

Closes #4325

Closes #4325

Add gutters properties (grid-gap, grid-column-gap and grid-row-gap):
https://www.w3.org/TR/css-grid-1/#gutters

Take advantage to add some missing keywors:
* grid and inline-grid: https://www.w3.org/TR/css-grid-1/#grid-containers
* dense: https://www.w3.org/TR/css-grid-1/#grid-auto-flow-property

It's been a while since the list of properties has been updated:
https://drafts.csswg.org/css-grid/#property-index

Issue #3625

Closes #3585

Closes #3475

Closes #3470

Closes #3417

Closes #3336

Issue #3253

Closes #3244

Issue #3164

[attr, calc, counter, counters, linear-gradient, matrix, matrix3d,
perspective, radial-gradient, repeating-linear-gradient,
repeating-radial-gradient, rotate, rotate3d, rotateX, rotateY, rotateZ,
scale, scale3d, scaleX, scaleY, scaleZ, skew, skewX, skewY, symbols,
translate, translate3d, translateX, translateY, translateZ, var]

And don't call delete on the state object.

Issue #3084

Add support for @counter-style blocks by making them and @font-face
blocks match a new "restricted_atBlock" state based on "font_face"

Teach it about @document in a more general way than my first attempt,
and also do @supports the same, by treating both them and @media as
atBlocks with shared word parsing

Issue #3066

Add support for the @supports rule

Issue #3064

Completing inside a word used to try and take the whole word into
account. This is not typical completion behavior, and often not what
you want. After this change, the addons only take the part of the
word in front of the cursor into account.

Issue #2922