Dereferencing tags' children in DSL 🔥

[quimt]

Is your feature request related to a problem? Please describe. 🤔
Now that buildHtml can generate fragments of DSL code, the next natural thing to do with them is to place them in more complex data structures other than simple assignments. Procs returning TagRefs and seqs/sets/tables of TagRefs are all valuable, but if simplicity is a priority, then simply having a convenient way to de-reference children would be enough.

Given that components can only have one slot, for example, accessing the children of slot allows components to have a variable number of TagRef arguments and post them to the page in more selective and complex ways.

Currently we can access children and assign to a variable, but cannot use [] directly to place a TagRef:

appRoutes("ROOT"):
  "/":
    let myList = buildHtml:
      tDiv: "a"
      tDiv: "b"
      tDiv: "c"
    let myItem = myList.children[2]
    myItem
    # myList.children[2]

The code will run and selects tDiv: "c", but the commented code fails. Currently the compiler says it expected an identifier but didn't get one; ideally it seems we want to allow any call that returns a static string or a Component or a TagRef

[Ethosa]

Since next commit you can do all of it with {} syntax: