Closes #4643

Closes #4609

Closes #4628

`{@inject}` is used for injected parameters instead of normal
parameters. It behaves the same as `{@param}`.

Closes #4635

Closes #4623

As per http://spec.commonmark.org/0.27/#html-blocks

Issue #4611

Issue #4603

Issue #4603

Closes #4599

Closes #4595

This reverts commit 81b7760c.

Closes #4590

Closes #4585

Issue #4497

Closes #4499

Closes #4573

Closes #4568

To forbid using the comment strings from their inner modes

Closes #4562

Closes #4563

Closes #4472

Closes #4553

  - Update keywords (remove `ifdef`. add `select`, `uninitialized` and `__END_LINE__`.)
  - Add new string literals (%q string and here docs).
  - Remove global variable syntax (because it is no longer supported.)
  - Improve indentation (fix #3887, and correct indentation of `abstract class`)

Closes #4545