extensions: Yet another PR for debugger touchups (#32822)

We'll now clean up DAP locators for unloaded extensions and load schemas
proper

I can now load a custom Ruby extensions with all bells and whistles and
use it as my debugger.

Release Notes:

- N/A

docs/src/extensions/developing-extensions.md

@@ -5,6 +5,7 @@
 Extensions can add the following capabilities to Zed:
 
 - [Languages](./languages.md)
+- [Debuggers](./debugger-extensions.md)
 - [Themes](./themes.md)
 - [Icon Themes](./icon-themes.md)
 - [Slash Commands](./slash-commands.md)