Fix docs validation to detect unknown keys (#49660)

Closes #ISSUE

Release Notes:

- N/A *or* Added/Fixed/Improved ...

---------

Co-authored-by: Zed Zippy <234243425+zed-zippy[bot]@users.noreply.github.com>

docs/src/languages/python.md

@@ -153,7 +153,7 @@ basedpyright reads project-specific configuration from the `pyrightconfig.json`
 
 Here's an example `pyrightconfig.json` file that configures basedpyright to use the `strict` type-checking mode and not to issue diagnostics for any files in `__pycache__` directories:
 
-```json [settings]
+```json
 {
   "typeCheckingMode": "strict",
   "ignore": ["**/__pycache__"]