Add purs-tidy formatter

Author: thomashoneyman

.github/workflows/ci.yml

@@ -15,6 +15,8 @@ jobs:
 
       - name: Set up a PureScript toolchain
         uses: purescript-contrib/setup-purescript@main
+        with:
+          purs-tidy: "latest"
 
       - name: Cache PureScript dependencies
         uses: actions/cache@v2
@@ -38,3 +40,6 @@ jobs:
 
       - name: Run tests
         run: spago -x test.dhall test --no-install
+
+      - name: Check formatting
+        run: purs-tidy check src test

.gitignore

@@ -2,6 +2,7 @@
 !.gitignore
 !.github
 !.editorconfig
+!.tidyrc.json
 
 output
 generated-docs

.tidyrc.json

@@ -0,0 +1,10 @@
+{
+  "importSort": "source",
+  "importWrap": "source",
+  "indent": 2,
+  "operatorsFile": null,
+  "ribbon": 1,
+  "typeArrowPlacement": "first",
+  "unicode": "never",
+  "width": null
+}