just prettier, just format shortcuts

Justfile

@@ -36,6 +36,13 @@ export DATASETTE_SECRET := "not_a_secret"
 @black:
   pipenv run black .
 
+# Apply prettier
+@prettier:
+  npm run fix
+
+# Format code with both black and prettier
+@format: black prettier
+
 @serve:
   pipenv run sqlite-utils create-database data.db
   pipenv run sqlite-utils create-table data.db docs id integer title text --pk id --ignore

docs/contributing.rst

@@ -131,6 +131,15 @@ These formatters are enforced by Datasette's continuous integration: if a commit
 
 When developing locally, you can verify and correct the formatting of your code using these tools.
 
+If you are using `Just <https://github.com/casey/just>`__ the quickest way to run these is like so::
+
+    just black
+    just prettier
+
+Or run both at the same time::
+
+    just format
+
 .. _contributing_formatting_black:
 
 Running Black