tweak code formatting rules

* output as "json-stringify" (which is most similar to most files currently in the repository)
* add .editorconfig
* drop (now) superfluous pretter settings
* add npm commands to check code style

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+[{data/deprecated.json,data/discarded.json,package.json,.package-lock.json}]
+indent_size = 2

.prettierignore

@@ -0,0 +1,6 @@
+package.json
+package-lock.json
+dist/
+*.yaml
+data/discarded.json
+data/deprecated.json

.prettierrc

@@ -1,8 +1,5 @@
 {
-	"tabWidth": 4,
-	"useTabs": false,
-	"semi": false,
-	"printWidth": 80,
+	"parser": "json-stringify",
 	"proseWrap": "never",
 	"bracketSpacing": true,
 	"endOfLine": "lf"

package.json

@@ -11,12 +11,15 @@
   "license": "ISC",
   "main": "build.js",
   "scripts": {
+    "lint": "prettier --check data",
+    "lint:fix": "prettier --write data",
     "build": "node scripts/build.js",
     "dist": "node scripts/dist.js",
     "test": "node scripts/test.js",
     "translations": "node scripts/translations.js"
   },
   "devDependencies": {
-    "@ideditor/schema-builder": "~4.0.5"
+    "@ideditor/schema-builder": "~4.0.5",
+    "prettier": "~2.5.1"
   }
 }