Enable some features to improve the programming experience (#1022)

* Update pxtarget.json

Enable addNewTypeScriptFile so that you can split your code into multiple files. Enable blocksCollapsing to collapse blocks for convenience. Turn off highContrast it doesn't work now. We'll see later...

* enable-errorlist-option

* Update pxtarget.json

Co-authored-by: Joey Wunderlich <jwunderl@users.noreply.github.com>

---------

Co-authored-by: Joey Wunderlich <jwunderl@users.noreply.github.com>

pxtarget.json

@@ -109,6 +109,8 @@
         "copyrightText": "LEGO, the LEGO logo, MINDSTORMS and the MINDSTORMS EV3 logo are trademarks and/ or copyrights of the LEGO Group. ©2018 The LEGO Group. All rights reserved.",
         "crowdinProject": "makecode",
         "selectLanguage": true,
+        "blocksCollapsing": true,
+        "highContrast": true,
         "greenScreen": true,
         "availableLocales": [
             "en",
@@ -118,7 +120,6 @@
             "zh-CN",
             "fr"
         ],
-        "highContrast": true,
         "lightToc": true,
         "docMenu": [{
                 "name": "Support",
@@ -160,7 +161,9 @@
         "extendFieldEditors": true,
         "scriptManager": true,
         "debugger": true,
+        "errorList": true,
         "importExtensionFiles": true,
+        "addNewTypeScriptFile": true,
         "experiments": [
             "python",
             "alwaysGithubItemBlocks"