SCM: Support input box spell checking

[borekb]

For longer commit messages it would be great to have a spell checker there. Ideally, VSCode would provide that out of the box but if the direction is to leave spell checking up to extensions (and there are already some great ones out there, like Spell Right by @bartosz-antosik), there could be an API for that.

Possibly related: Offline spell checker for VSCode #20266

UPDATE: since 2020, Electron supports spell checking natively, see below.

[joaomoreno]

This could be interesting: https://github.com/electron-userland/electron-spellchecker

[einarolafs]

This would be a very valuable feature, there is nothing worse than creating a spelling mistake in a commit and discovering many commits later.

[skprabhanjan]

@joaomoreno , Working on this and using https://github.com/electron-userland/electron-spellchecker as suggested.

[skprabhanjan]

@joaomoreno , I tried various ways of using that module but keep getting an error("Activating extension 'vscode.git' failed: Cannot find module 'electron-spellchecker'.), can you please share any example of how to install and use an external module like electron-spellchecker?
Thanks :)