lint.sh: fix sed command

Author: rffontenelle

scripts/lint.sh

@@ -19,7 +19,7 @@ mkdir -p logs
 touch logs/sphinxlint.txt
 
 # Disable literal blocks and update PO
-sed -i "s/^\s*'literal-block',/s/ '/ #'/" cpython/Doc/conf.py
+sed -i "/^\s*'literal-block',/s/ '/ #'/" cpython/Doc/conf.py
 ./scripts/generate_templates.sh
 sphinx-intl update -d cpython/Doc/locale -l pt_BR