Fix sh code block in README (#93)

jdillard · web-flow · commit 84d17a721126 · 2023-10-14T06:45:23.000+02:00
It wasn't closed properly
diff --git a/README.md b/README.md
@@ -31,6 +31,7 @@ sphinx-lint file.rst  # check a single file
 sphinx-lint docs      # check a directory
 sphinx-lint -i venv   # ignore a file/directory
 sphinx-lint -h        # for more options
+```
 
 Sphinx Lint can also be used via [pre-commit](https://pre-commit.com).
 We recommend using a configuration like this:
