Update README.md

Author: erikw

README.md

@@ -109,7 +109,7 @@ bin/fetch_input.sh yy/mm
 ```
 
 > [!TIP]
-> The default language could be set with an envvar, e.g. with dotenv in a `.env` file which is also read by `bin/solve_day.sh`:
+> The default language can be set with an envvar, e.g. with dotenv in a `.env` file which is also read by `bin/solve_day.sh`:
 > ```shell
 > echo AOC_LANG=py >> .env
 > ```