Allow template-variables in a header-path in a capture-template

[jbhoot]

Is your feature request related to a problem? Please describe.

I file my thoughts/observations/todos/notes of a day under a main headline titled as the timestamp of that day. For eg:

* [2020-07-08 Wed]
** After breathing for a couple of hours in a mask, I understand why Superman chose a pair of glasses and a curly lock of hair to hide his identity. :thoughts:
** A Time to Kill :watch:
** being bald: you immediately know when a fly has landed on your hair :thoughts:

* [2020-07-07 Tue]
** TODO Set up quick screenshotting in Zoom and Windows 7 :wife:
** Corona FAQ: :thoughts:
Q: Should I wear a mask while driving?
A: If you usually speed through red lights, then don't bother.

So the headline under which I want to use capture-templates are dynamic.

Describe the solution you'd like
Allow the use of template-variables in the header-path in a capture-template. So I could simply use %u as my header-path.

Describe alternatives you've considered
Another way could be to allow adding a subheadline under (instead of below) a zoomed-in/narrowed-in headline.

[munen]

Hi @jayesh-bhoot

Thank you for checking out organice! Would you be interested to building this feature?

[jbhoot]

So I gave this a shot. I think I have figured it out. video demonstration on imgur

I have kept the changes to a minimum -

1. Parse the template-variables in a header with substituteTemplateVariables() in headerWithPath(), so that the template-variables are processed wherever headerPath is touched (I think so atleast).
2. Parse the template variables in a header with substituteTemplateVariables() to display the header-path correctly in the capture-modal.

While all the existing tests pass, I think I should add a few tests to cover this change as well.

[munen]

From the video, it looks great! 🎉

Adding tests for the specific new feature is much appreciated!

[jbhoot]

@munen See if the PR #387 satisfies this issue.

[munen]

@jayesh-bhoot Perfect implementation!

I've added a tiny bit of documentation and the contribution attribution.

Happy to merge it in! Welcome to the organice contributor list 🙏 🙇