Add a text-to-speech demo

[bruvzg]

Adds a demo for godotengine/godot#56192

[lesleyrs]

Hey you are really awesome for adding this to Godot!

I just played around with the demo for a bit and it's great for some use cases even outside of games.

Windows Narrator takes over your entire PC and doesn't allow you to use any keys because they're all keymapped to a billion things. So you can't multitask.

I think this is very powerful being able to effectively turn almost anything into an audiobook, offline, with your own key shortcuts.

This is for you: 👑

A few problems though:

This and it only detects en-us voice on Windows 10 even if I set the other language to be the default narrator (dutch).

Regedit screenshot here showing frank: https://i.imgur.com/yyfls5U.png

Edit: Something you can do with this that I really like is:

DisplayServer.tts_speak(DisplayServer.clipboard_get(), vc[0], 50, 1, 1, id + 1)

So you can copy something, use a stop and play shortcut and it just starts narrating anything you copy without pasting!

I'm having a little struggle right now to find out how to make it speak both demo lines though, it just skips to the 2nd one right away if you don't comment it out.

Edit2: also tts_resume() doesn't work on windows? You can just hit play to resume though.

[Calinou]

Thanks!

(I've pushed a second commit with cosmetic changes, but the behavior is the same.)