update attach parameter table in the README

Author: matthewbastien

lldb/tools/lldb-dap/README.md

@@ -250,8 +250,8 @@ the following `lldb-dap` specific key/value pairs:
 | Parameter                         | Type        | Req |         |
 |-----------------------------------|-------------|:---:|---------|
 | **program**                       | string      |     | Path to the executable to attach to. This value is optional but can help to resolve breakpoints prior the attaching to the program.
-| **pid**                           | number      |     | The process id of the process you wish to attach to. If **pid** is omitted, the debugger will attempt to attach to the program by finding a process whose file name matches the file name from **program**. Setting this value to `${command:pickProcess}` will allow interactive process selection in the IDE.
-| **waitFor**                       | boolean     |     | Wait for the process to launch.
+| **pid**                           | number      |     | The process id of the process you wish to attach to. If **pid** is omitted or set to `"${command:pickProcess}"` then the extension will show a process picker with a list of running processes on the system. Choosing one of these process will launch a new debug session where `lldb-dap` will attach to the chosen process.
+| **waitFor**                       | boolean     |     | Wait for a new process that matches the **program** basename to launch. The process picker will not be shown in this case.
 | **attachCommands**                | [string]    |     | LLDB commands that will be executed after **preRunCommands** which take place of the code that normally does the attach. The commands can create a new target and attach or launch it however desired. This allows custom launch and attach configurations. Core files can use `target create --core /path/to/core` to attach to core files.
 
 ## Debug Console