New feature for options.params

[Realharon]

Added support for use callback function instead of dictionary in
options.params. This need for dynamically set custom Ajax parameters.

Example:

$(el).autocomplete({
    params : function() {
        return {
            foo : this.dataset.foo,
            bar : this.dataset.bar,
            baz : this.id,
            val : this.value
            ... etc. as you wish ...
        };
    }
});

[tkirda]

Thanks for this contribution, and apologies for the very long silence.

The project was dormant for several years and has just shipped v2.0, which is a ground-up TypeScript rewrite with a new build (esbuild), test runner (Vitest + jsdom), and CI pipeline. As a result this PR no longer applies cleanly against master, and the surrounding code it touches has changed enough that mechanically rebasing it wouldn't be safe.

I'm closing it as part of a triage pass on the long-stale PR backlog — not because the idea lacks merit. If this change is still valuable to you against 2.0, please open a fresh PR (or an issue first if you'd like to confirm direction); I'll review new submissions against the current codebase promptly.

Thanks again for taking the time.