Closes #3864

Closes #3802

This allows findModeByName to work for edn and seems more consistent
with how JSON is handled.

Closes #3846.

Closes #3849

Closes #3853

Issue #3852

When hovering a line with multiple lint annotations, codeMirror will
now show all the attached markers instead of just the first one

Closes #3847

Closes #3846

 * Support nested block comments.
 * Improve number and operator parsing.
 * Improve string parsing.
 * Style brackets correctly.
 * Improve #-words.

Fixes #3842.

Closes #3840

It's already listed above as "MariaDB SQL".

Also add the ".mps" extension to the MUMPS mode.

Closes #3834

Issue #3821

Rather than hard-coding the bare XML mode.

Issue #3829

`serializeable` → `serializable`
Replace `an` with `a` 
Remove extra `command`

See https://discuss.codemirror.net/t/any-way-to-override-syntax-error-highlighting-in-asp-net-like-code/642

Closes #3808

This patch enables styling of active line numbers by
adding a `CodeMirror-activeline-gutter` class to the
line's gutter space.