customized proof-view.css is overwritten by updating the extension

[siegebell]

Updating vscoq causes user-customizations to proof-view.css to be overwritten.

Possible resolutions:

1. Store proof-view.css in the workspace-settings folder. This means that it will be specific to one project and would have to manually copied to all other projects. I dislike this approach because most users would expect their color/style changes to be universal.
2. Store proof-view.css in a per-user settings folder. Ideally, vscode would tell extensions where they can store user settings; but this is not yet implemented (Microsoft/vscode#2741). I could calculate where vscode puts such settings, but it is very likely to change in the next release or two. Otherwise, I can manually calculate where user settings should go -- this is not trivial because Linux, OS X, and Windows all have different expectations... and this would make adopting vscode's proscribed approach a breaking change when it becomes available.

@jonleivent fyi

[siegebell]

@jonleivent when 0.2.6 is released, you can set coq.hacks.userSettingsLocation to a directory that won't be overwritten when the extension is updated. proof-view.css will be stored in this directory, if specified.

Note: I will likely remove coq.hacks.userSettingsLocation when vscode eventually gets an equivalent feature.

[jonleivent]

If I put a proof-view.css file in coq.hacks.userSettingsLocation, is it used instead of the normal proof-view.css, or in addition to it?

[siegebell]

Instead of (hopefully...)