[lldb][lldb-vscode] Add example configuration for connecting to a remote gdbserver (llvm#68866)

This can be used to have VS Code debug various emulators, remote
systems, hardware probes, etc.

In my case I was doing this for the Gameboy Advance,
https://github.com/stuij/gba-llvm-devkit/blob/main/docs/Debugging.md#debugging-using-visual-studio-code.

It's not very complex if you know LLDB well, but when using another
plugin, CodeLLDB, I was very glad that they had an example for it. So we
should have one too.

(cherry picked from commit 4606712)

Author: DavidSpickett

lldb/tools/lldb-vscode/README.md

@@ -212,6 +212,38 @@ This loads the coredump file `/cores/123.core` associated with the program
 }
 ```
 
+### Connect to a Debug Server on the Current Machine
+
+This connects to a debug server (e.g. `lldb-server`, `gdbserver`) on
+the current machine, that is debugging the program `/tmp/a.out` and listening
+locally on port `2345`.
+
+```javascript
+{
+  "name": "Local Debug Server",
+  "type": "lldb-vscode",
+  "request": "attach",
+  "program": "/tmp/a.out",
+  "attachCommands": ["gdb-remote 2345"],
+}
+```
+
+### Connect to a Debug Server on Another Machine
+
+This connects to a debug server running on another machine with hostname
+`hostnmame`. Which is debugging the program `/tmp/a.out` and listening on
+port `5678` of that other machine.
+
+```javascript
+{
+  "name": "Remote Debug Server",
+  "type": "lldb-vscode",
+  "request": "attach",
+  "program": "/tmp/a.out",
+  "attachCommands": ["gdb-remote hostname:5678"],
+}
+```
+
 # Custom debugger commands
 
 The `lldb-vscode` tool includes additional custom commands to support the Debug