Support for nested tags.

[v-shenoy]

It would be great if tags could be organized hierarchically by nesting them such as

• #maths/algebra
• #maths/calculus

With this if you wanted to prepare for an upcoming algebra test you could query your notes using

```query
maths/algebra
```

while if you wanted to query all your math notes you could use

```query
maths
```

I understand that you it is possible to tag your notes individually with #maths and #algebra. But it means that you have to remember to tag all your #algebra notes with #maths as well.

To elaborate bit more on my workflow, I have some top-level folders for certain categories but beyond that I use tags for organization. This is beneficial since notes can be tagged multiples times without worrying what subfolder they are under in a completely folder based workflow.

This might be a consequence of trying to use an Obsidian-esque workflow in SilverBullet, but I thought it wouldn't hurt to ask.
Obsidian tags ref.