Closes #4030
Closes #4031

Closes #3926
Closes #4026

To make it clearer that they are updated together

Issue #4028

Closes #3983

Closes #745

This reverts commit 8dbb84f4.

Issue #3127

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

1. Mention multiplex as a dependency
2. Add ERB as a MIME-type

Closes #4025

Issue #2901

Issue #4022

Closes #4020

Closes #4012

Closes #4009

Issue #4013

Closes #4013

Closes #3998

Closes #3994

* \x1a-\x1f were missing though it looks like the intention was to cover all below \x20 (space)
* added \x7f which is usually considered non-printable
* removed \t which was already covered in \x00-\x19 as \x09

Issue #3979

Issue #4001

Use it to make the C++ mode not indent template statements

Closes #4001

according to Clojure's changelog: https://github.com/clojure/clojure/blob/master/changes.md

Issue #3991

Closes #3981

See https://discuss.codemirror.net/t/drag-drop-modifiers/721

"commend addon" should be "comment addon".