Fix markdown lists in docstrings

[abhro]

Checklist

• Appropriate tests were added
  None applicable
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the contributor guidelines, in particular the SciML Style Guide and COLPRAC.
• Any new documentation only uses public API

Additional context

In the two(?) docstrings for EnsembleProblem, the first one has list fragmentation, since the list content is not all indented at the same level after the list marker (-).
In the second list, the 4-space indent is detected by Documenter.jl as a code block and the list aspect ignored.