I have a document with hundreds of org headings, sorted alphabetically. I would like to find a way of jumping to the first visible heading whose initial letter(s) match the string typed so far. (Intuitively, the functionality I am trying to replicate resembles that of some file managers such as OSX Finder, where one can quickly jump to any file or directory just by typing the first few letters of it, with the difference being that the candidates here are instead visible org headings.)

For example, suppose that the first few lines of my document look like this:

```
* AlphaGo
AlphaGo is a computer program that plays the game Go. It should not be confused with AlphaZero.
** Gamma
* AlphaZero
* Beta
* Gamma

```

Then (assuming point is at the beginning of the document) typing `a` would move point to the first line, typing `alphaz` would move point to the fourth line, and typing `g` would move point to the final line if the first heading is folded, and to the third line otherwise.