Expand markdown-ts-mode and add code block support for javascript

Expand markdown-ts-mode and add code block support for javascript

- Define new faces and use them in place of font-lock faces
- Add more fontification, add a new feature for headings.
- Remove fontification for code blocks, so embedeed parser can
  fontify them
- Add experimental code block support for javascript by using
  tree-sitter setup from js-ts-mode.
- Correctly setup markdown_inline with range settings.

* lisp/textmodes/markdown-ts-mode.el:
(markdown-ts--code-block-language-map):
(markdown-ts-code-block-source-mode-map): New variables.
(markdown-ts-faces): New group.
(markdown-ts-delimiter):
(markdown-ts-heading-1):
(markdown-ts-setext-heading):
(markdown-ts-heading-2):
(markdown-ts-heading-3):
(markdown-ts-heading-4):
(markdown-ts-heading-5):
(markdown-ts-heading-6):
(markdown-ts-list-marker):
(markdown-ts-block-quote):
(markdown-ts-language-keyword): New faces.
(markdown-ts--treesit-settings):
(markdown-ts--configured-languages): New variables.
(markdown-ts--harvest-treesit-configs):
(markdown-ts--add-config-for-mode):
(markdown-ts--convert-code-block-language): New functions.
(markdown-ts--range-settings): New variable.
(markdown-ts-setup): Setup range configuration.
(markdown-ts-mode): Add heading feature.

(cherry picked from commit 6f1e317764dab918d40b08d2e8e9166d42ae6c8d)