Issue #12344

**Bug**
Current colorization rules are too relaxed. Links inside lists of block quotes for example end up getting colored differently than normal links.

**Fix**
- Add a scope to the textmate markdown grammar so that we can identify the symbol that starts a list or quote.
- Remove text colorization rule for lists and quotes since this just duplicates the normal text color.
- Only apply special puctuator colorization to the start symbol for lists and quotes