Index wikilinks in frontmatter strings

[Maarrk]

This implements #1000

The link is indexed only if it is the full content of a string node (allowing for quotes and whitespace) to discourage writing essays in the frontmatter 😄

I added an explanation why the quotes are needed on YAML page, I can't think of a page to document that the feature exists at all, I think it's discoverable by looking at indexPage in SETTINGS

[Maarrk]

Short demo of what it allows, credit to Raphwriter

[Maarrk]

Would be nice to make them clickable, but I think that becomes a much larger feature, since they shouldn't hide the [[ ]] like links in normal text do when cursor is away. Same for tags in frontmatter.

Considering #736 this would be almost like another editor mode when inside frontmatter: different widgets, different autocomplete etc., I don't know how I would approach that. Hope this bit here helps

[zefhemel]

I have this test page:

---
another: "[[nice page]]"
---
This is a nice page [[nice page]]!

```query
link where page = @page.name
```

I would expect 2 entries in link, one for the regular page link and one for the frontmatter. And sometimes I get this, but not always. I make a small edit, let it save and Alt-q and it's there, and sometimes it's not. Do you have any idea what could be going on here? Some sort of race condition?

Then, when I rename another page I would expect both these links to be updated, but that's also not happening. Perhaps it's related to this indexing not happening consistently though... Can you replicate this?

[Maarrk]

Funnily enough, it did work in a small test space, but in my main one, I can't get the frontmatter mention to show up at all. I will look into it more these days, thanks for the heads up 👍