Closes #3650

`@ng1.Injectable` is a legal annotation

`import "package:foo/foo.dart" as bar;` should highlight "as" as a keyword.

Closes ##3648

Make this the default

Issue #3636

Moving the mouse will change the selected hint option

So that the annotations still make sense when scrollPastEnd is enabled

Closes #3630

Closes #3623

In a raw string, a character following a "\" is not escaped.

Issue #3625

it seems `.cm-error` lost some specificity in [this commit](https://github.com/codemirror/CodeMirror/commit/a7d443ec82c1806d24e25ad8014a4d8651409320#diff-33646e9ee4d04eedb98a991a636c2302L35) that causes the error state to have same color as the tag.

Issue #3517

We now disable pointer events on them (again) and temporarily
re-enable those when scrolling.

Fixes a problem where you could not click to put the cursor
'under' the hidden scrollbar areas at the right and bottom.

Issue #2326

Closes #3569

Issue #3581

Issue ternjs/tern#668

Added: filter, endfilter, elif, endblocktrans, endspaceless

Closes #3616

Since collapsing might move previously hidden code into the viewport

Issue #3599

Issue #3607

Closes #3592

Issue #3593

Issue #3586

The `markdown` mode now supports styling overrides. The configuration
object passed to the class now accepts a `tokenTypeOverrides` object,
which allows the user to sepcify different CSS classes for elements.
This is useful for the case where the default CSS classes are reused
for multiple elements (e.g. `list1` maps to `variable-2` by default)
and more customized styling is desired.

Unit tests have been added to cover all types of styling overrides.