Closes #2816

Closes #2813

after header immediately followed by a code block, GFM formatting is
broken (SHA, #issue, URLs).

overlay.codeBlock gets it wrong (false inside fenced block, true after).
Not yet sure why.

Added hawkee.com

Throwing exceptions is a really bad way to deal with unexpected
syntax in a highlighting mode.

Closes #2805

Closes #2810

To make it easy for client code to color completions without clashing
with the selected styling.

Code: Brackets now become black when they are highlighted as "matching".
JSON: key names are now in "white" (json was a bit saturated with orange - keys and string values).
Cleanup: removed some unnecessary rules.
Default face color normalized to #ffffec (was #ffffe9).

Closes #2804

Closes #2796

Closes #2794

It now closes script and style tags when the slash is typed

Closes #2797

It does not happen when measuring a node

Issue #2665

Issue #2765

Issue #2792

Issue #2786

Issue #2714

Fixes detection of Hebrew letters as word characters

Closes #2789

Closes #2783

Closes #2790

Issue #2780