Add notes count to details summary line

[MHoeller]

Story

As a user I want to see the count of notes it a details summary line when the summary is not opened, so that I can see if the filter returns content without opening the details

Example

Code

<!-- note-overview-plugin
search: -tag:*
fields: title
details:
  open: false
  summary: All notes without a Tag  - **Notes count {{ count }}**
-->

Result

All notes without a Tag - Notes count 42