Closes #5059

Per #5030, when adding new items to the middle of a Markdown list, the remaining list numbers should automatically increment

Issue #5054

To also make sure the last token isn't a string.

Issue codemirror/google-modes#74

The markdown mode uses `CodeMirror.innerMode` which isn't defined in
the stripped down node runmode. Since markdown is the only mode
(AFAICT) that uses it I'm not sure if it would make more sense rewrite
it to not use it but this seemed like the least risky option.

Issue #5031

The addon would think it still was in a block comment when
one was opened and closed earlier on the line.

Issue codemirror/google-modes#58

Closes #4954

Closes #4970

Closes #4963

Issue #4956

Linters like JSHint will complain if rules are mixed with the options for the linter addon, like onUpdateLinting and delay.

Fixes #4935.

Issue #4922

* Pass in and use the htmlhint module required.
* Check for verify() and try HTMLHint.HTMLHint if missing because of
  module nesting. it's require('htmlhint').HTMLHint in node.

Issue codemirror/google-modes#8

This is opt-in, the plugin needs to produce message_html instead of
message to be rendered as HTML.

This should help developers building this functionality out that may not
realize they need to source the linting library seperately.

Issue #3059

So that the addon doesn't try to put a single DOM node in two places

Closes #4848

Issue #4839

Closes #4839

Issue #4824

This prevents the test case search_expandingCaseFold from hanging in
Firefox 54 on Linux.

Issue #4819

Issue #4784

Issue #4787