Desktop, Mobile: Fixes #10891: Markdown editor: Fix toggling bulleted lists when items start with asterisks

[personalizedrefrigerator]

Summary

This pull request requires a space after the starting * or - in a bulleted list. Previously, markup similar to **test** was considered a bulleted list item by the list-toggling regular expression.

This should fix #10891.

Notes

When continuing or creating a new bulleted list with toolbar buttons, a space seems to be automatically added after the leading -. As such, it shouldn't be necessary to handle the case where - is followed by an end-of-line or end-of-document.

Testing plan

1. Start the desktop app (CodeMirror 6 markdown editor enabled).
2. Create a new note with the following content:

   **test**
   test
   *test*
   
   1. This
   2. is
   3. a
   4. test
   
   List:
   - This
   - is
     a
   - test
       - TEST!
   

3. Select

   **test**
   test
   *test*
   

4. Click the "toggle bulleted list" button.
5. Verify that the selected items are now in a bulleted list.
6. Click "toggle bulleted list" again.
7. Verify that the bulleted list has been removed.
8. Select the bottommost bulleted list and click "toggle bulleted list".
9. Verify that the bulleted list has been removed.
10. Add a header near the end of the document on a blank line. Press enter.
11. At the end of the document, press "toggle bulleted list".
12. Type.
13. Verify that a single bulleted list item has been added.