Made function 'start' in 'lua/flutter-tools.lua' public

[obemu]

This PR changes the visibility of the function start in lua/flutter-tools.lua from private to public.

Currently, it is not possible to execute user commands from flutter-tools (FlutterRun, FlutterDebug, ...) before a .dart or the pubspec.yaml file has been entered. These commands can only be used once the start function, which registers them, is called. The problem is, that instead of calling start in setup, it is called once a .dart or the pubspec.yaml file is entered.

This change allows the user to call flutter.start() in their init.lua (or local .nvim.lua) file, to register all user commands. Therefore, the user is not required to enter a .dart/pubspec.yaml file to run their app and view log messages.

[sidlatau]

Registering commands in .nvim.lua is already supported via this pull request. I'm not sure if exposing the start function adds significant value. Could you elaborate on the specific use case this PR addresses?

[obemu]

I took a closer look at setup_project and found that I can achieve my desired outcome (being able to use the user commands without entering a .dart/pubspec.yaml file) by calling flutter.setup_project({}) in my init.lua. So accepting the PR would not add any new feature.

Nevertheless, I still think that there is some value in my approach, because I think that

local flutter = require("flutter-tools")
flutter.setup({ ... })
flutter.start()

semantically makes a lot more sense than

local flutter = require("flutter-tools")
flutter.setup({ ... })
flutter.setup_project({})