Markdown template does not respect `all_bullets=false`

[LecrisUT]

A quick check at the template seems to show that - is always added to the content.

towncrier/src/towncrier/templates/default.md

Lines 18 to 19 in cb09ddf

	{% for text, values in sections[section][category].items() %}
	- {{ text }}

Extra nice if this can be set for each section individually

[adiroiban]

Thanks for the report.

I am happy to review and merge an update to the default.md file that implements support for all_bullets