New config option: `trailing_spaces_scope_ignore`

[smanolloff]

Also, remove mentions of the inferior trailing_spaces_syntax_ignore option in the README (still considered in the code for backward compat).

Default value:

// Trailing spaces for find results and build output are ignored
"trailing_spaces_scope_ignore": ["text.find-in-files", "source.build_output"]

This PR supersedes #98 (which I will now close).

This is a more flexible variation of the syntax ignore setting, as it provides fine-grained control over the ignored matches.

[FichteFoll]

I like this, but it will take some manual effort to merge this along with the others PRs currently.

[rchl]

I think syntax ignoring should still be a first-world citizen and not just deprecated as scope matching is not gonna help with Terminus which runs in text.plain scope. And I would consider Terminus to be important enough to warrant keeping that functionality.

EDIT: Actually Terminus is also using plain text syntax so can't exclude by syntax either.

[FichteFoll]

Maybe exclude scratch views?

[rchl]

Could do but:

• then the functionality will not work newly created, unsaved views
• if added, should it be a setting?
• if a setting, what should be the default?

Whatever we do, someone will complain anyway :)

[FichteFoll]

Unsaved views are not scratch views. It should be fine as the (unconfigurable) default since scratch views can only be created by plugins.

[rchl]

Since this is so old PR and I'm not sure if the author still has an interest in it, I've merged change manually as 6bf6b8801622a990f54cf336605e4d7290c573df with fixes for my comments applied.

Thanks for working on it and sorry it took so long. :)