perf(lsp): cleanup workspace settings scopes

[nayeemrmn]

Before we were fetching and storing workspace/configuration for every opened document. But VSCode (for example) only respects differing .vscode/settings.json files per workspace folder.

This removes SpecifierSettings and simplifies our settings storage to the following:

pub struct Settings {
  pub unscoped: WorkspaceSettings,
  pub by_workspace_folder: Option<BTreeMap<ModuleSpecifier, WorkspaceSettings>>,
}

Initially, the unscoped field is populated with whatever was passed in the LSP init options. After that and on each config change event, if the client supports workspace/configuration requests, we fetch settings scoped for each workspace folder plus another 'unscoped' one to use as a fallback and to replace the stale init options.

The usage of these is abstracted under a Config::workspace_settings_for_specifier() method.

[dsherret]

LGTM!

[dsherret]

Why maybe remove the builder?

[nayeemrmn]

There's too many ways of supplying config, there's a separate arg for that and the value has to be saved to keep supplying it on configuration requests. The builder makes it complicated

[dsherret]

Maybe we should keep the initialization parameters and config separate? They seem to be starting to blend together here. I'm not sure though.

[nayeemrmn]

Oh right, yeah not the whole builder but just make the InitializeParams::initializationOptions part of it (which accepts workspace settings) into one value setter.