Simplify description of executablePath setting

"This overrides all other CodeQL CLI settings" is a potential source of
confusion, since it suggests the RAM and threads settings may not be
passed to custom CLIs, when this is in fact the case.

Author: henrymercer

extensions/ql-vscode/package.json

@@ -114,7 +114,7 @@
           "scope": "machine",
           "type": "string",
           "default": "",
-          "description": "Path to the CodeQL executable that should be used by the CodeQL extension. The executable is named `codeql` on Linux/Mac and `codeql.exe` on Windows. This overrides all other CodeQL CLI settings."
+          "description": "Path to the CodeQL executable that should be used by the CodeQL extension. The executable is named `codeql` on Linux/Mac and `codeql.exe` on Windows. If empty, the extension will look for a CodeQL executable on your shell PATH, or if CodeQL is not on your PATH, download and manage its own CodeQL executable."
         },
         "codeQL.runningQueries.numberOfThreads": {
           "type": "integer",