add info about config and remove linting specific files

Author: simp4t7

src/tools/tidy/Readme.md

@@ -68,12 +68,7 @@ Any argument without a suffix (eg. `py` or `js`) will include all possible check
 
 Any argument can be prefixed with `auto:` to only run if relevant files are modified (eg. `--extra-checks=auto:py`).
 
-
-`extra-checks` always runs in addition to the base tidy run. Additionally, you can pass in a specific file or directory to check only those files with an `extra-check`. For example:
-
-`./x test tidy --extra-checks=py -- src/bootstrap` will check all `.py` files recursively within the `/src/bootstrap` directory.
-
-`./x test tidy --extra-checks=py:lint -- src/bootstrap/bootstrap.py` will lint the single `.py` file specified.
+A specific configuration file or folder can be passed to tidy after a double dash (`--extra-checks=py -- foo.py`)
 
 ## Tidy Directives