Document how to filter by the field whose value is the link to the current page

[leventov]

https://blacksmithgu.github.io/obsidian-dataview/query/queries/

Describe the problem
Let's say I have a link-valued page attribute system. I want to have a template for pages that shows all files that have this attribute equal to the link to the current page.

The only solution that I've found working after long trial and error was:

```dataviewjs
dv.table(["File"], dv.pages()
  .where(p => p.system.path == dv.current().file.path)
  .map(p => [p.file.link]))

And, remarkably, no way to make such a query using Dataview query syntax. Or, at least I haven't found a way to do this.

I think would be nice to document this, maybe adding to the query examples.

[mnvwvnm]

In DQL:

TABLE WITHOUT ID file.link AS "File"
WHERE system = this.file.link

[AB1908]

Thanks for the suggestion!