Add support for 'comment' instruction

[claremacrae]

As part of testing the addition of a group by command, I'm going to be adding that to a bunch of notes.

But then when I want to revert to the released version, such as to compare behaviours and see if I have broken anything, I will have to remove all those lines. And reinstating them will be tedious.

I propose adding a syntax for comments...

I would suggest:

'''tasks
# group by path

Basically, anything where the first character is # will be ignored...

Would you accept a PR for this @schemar ?

[schemar]

Yes, happy to merge that. Please remember the documentation. Thank you!!

[claremacrae]

Super - thank you. It didn't take long at all...

#532

[schemar]

Will be in the next release. It will still take me a few weeks until I can make the next release, please be patient 😊