Allow disabling diagnostics

[plexus]

Calva receives various diagnostics from clojure-lsp (which gets most but not all of these from clj-kondo), it then displays them as squiggly annotations.

Not everyone wants this, I mostly perceive these as noise. People with ADHD in particular may find these really troublesome.

I could not find a way to disable these. Calva and clojure-lsp don't seem to have a flag for it. I couldn't find a way to tell VS Code to ignore linting/annotations. The best you can do right now is to disable linters in clj-kondo, but not all diagnostics are coming from clj-kondo (e.g. unused namespace, unused public are coming from clojure-lsp itself).

I'm testing out a patch that adds a configuration flag for this, essentially this:

// package.json
                    "calva.displayDiagnostics": {
                        "type": "boolean",
                        "markdownDescription": "Show linter warnings and other diagnostics from clojure-lsp and clj-kondo.",
                        "default": true
                    }

// lsp.ts
        middleware: {
            handleDiagnostics(uri, diagnostics, next) {
                if (!state.config().displayDiagnostics) {
                    return;
                }

If it works I can send a PR, meanwhile happy to get some input on this. Is this a reasonable place to handle this? Any opinions on the config flag / description?