* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

Make doctor output consistent between VS Code/IntelliJ/Android Studio when plugins are missing (#25269)

* Update VS Code validator to match Android Studio

- Now shows a tick (instead of partial) if installed
- Now shows a cross (instead of dot) if extension is not installed

Fixes #22931.

It's not usual for this not to be set, but it affected at least one user (#23909) and there are a non-zero number of people online saying it's not set. It's better that we don't crash.

Fixes #23909.

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

Fixes the pattern for some TODOs to match our style guide.

(Also, a couple of minor code order fixes.)

* Fixes resulting from audit of issues links

I looked at every link to GitHub in our repo. For cases where we had a TODO that was waiting for a bug to be fixed, and the bug has now been fixed, I applied the pending change. For cases where the link was out of date, I updated the link.

* Update run_test.dart

skip this test again since it failed on linux and macos bots

Fixes #18995.

Seems like VS Code may have started using lowercase extension folders recently (our identifier is `Dart-Code.flutter` but now the folder is named `dart-code.flutter`), so this makes the check not sensitive to casing.

Also reuse extension identifier for download link

Fixes #15198.

* Show 32/64bit in VS Code headings on Windows

Fixes #14949.

Looks in default install locations on Mac, Linux and Windows for VS Code. If found, looks in default extension location to see if Dart Code is installed.

If VS Code is not installed, nothing is reported. If VS Code is installed without Dart Code, a warning is shown.