add VS Code settings for formatting and file associations

Author: matracey

.vscode/settings.json

@@ -0,0 +1,30 @@
+{
+  "editor.formatOnPaste": false,
+  "editor.formatOnSave": false,
+  "editor.formatOnType": false,
+  "editor.tabSize": 4,
+  "files.associations": {
+    "*.csproj": "xml",
+    "*.sln.dotsettings": "xml"
+  },
+
+  "dotnet.defaultSolution": "./SystemTextJson.JsonDiffPatch.sln",
+  "[csharp]": {
+    "editor.defaultFormatter": "ms-dotnettools.csharp"
+  },
+
+  "prettier.printWidth": 180,
+  "[json,jsonc]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode",
+    "editor.formatOnSave": true,
+    "editor.tabSize": 2
+  },
+
+  "[xml]": {
+    "editor.defaultFormatter": "DotJoshJohnson.xml"
+  },
+  "[markdown]": {
+    "editor.defaultFormatter": "DavidAnson.vscode-markdownlint"
+  },
+  "markdown.extension.toc.levels": "1..3",
+}