Simplify debug launcher UI (#31928)

This PR updates the name of the `NewSessionModal` to `NewProcessModal`
(to reflect it's new purpose), changes the tabs in the modal to read
`Run | Debug | Attach | Launch` and changes the associated types in code
to match the tabs. In addition, this PR adds a few labels to the text
fields in the `Launch` tab, and adds a link to open the associated
settings file. In both debug.json files, added links to the zed.dev
debugger docs.

Release Notes:

- Debugger Beta: Improve the new process modal

crates/paths/src/paths.rs

@@ -408,6 +408,7 @@ pub fn task_file_name() -> &'static str {
 }
 
 /// Returns the relative path to a `debug.json` file within a project.
+/// .zed/debug.json
 pub fn local_debug_file_relative_path() -> &'static Path {
     Path::new(".zed/debug.json")
 }