Ability to configure list numbers and symbols

[ArtFlag]

Thanks for this cool extension 👍

I'd like to suggest adding the ability to config list numbers and symbols.

For instance:

• defining - as the only list symbol.
• defining 1. as the only numbered list symbol.

It's always a pain to see lists like:

1. a
2. b
3. c

When markdown supports the following which helps when you need to reorganize steps 👍

1. a
1. b
1. c

[Pxtl]

Ideally I'd want the reverse - when I run "format" it would convert

1. a
1. b
1. c

to

1. a
2. b
3. c

and otherwise correct any aberrations in number ordering. The whole idea of Markdown is that it's supposed to be as legible in text as it is when converted into a markup document, and "1. 1. 1." is less useful than properly numbered numbers.