doc: update README

Author: dshemetov

README.md

@@ -91,11 +91,11 @@ then it's likely because your local main branch is not up to date; either you
 need to rebase or merge. Note that `darker` reads from `pyproject.toml` for
 default settings.
 
-If the lines you change are in a file that uses width 2 tabs (which are plenty
-in this repo), it will only change those lines and not the rest, which will
-likely break the code; in that case, you should probably just pass the whole
-file through black and just do it in the same commit. You can do that with the
-following command (using the same virtual environment as above):
+If the lines you change are in a file that uses 2 space indentation, `darker`
+will indent the lines around your changes and not the rest, which will likely
+break the code; in that case, you should probably just pass the whole file
+through black. You can do that with the following command (using the same
+virtual environment as above):
 
 ```sh
 black <file>