Classify private identifiers in semantic tokens - #64349

ECMAScript private names are PrivateIdentifier nodes, so the semantic-token collector omitted them while classifying ordinary identifiers. Consequently, private fields and methods fell back to TextMate highlighting.

class Foo {
    #field = 1;
    #method() {}

    test() {
        this.#field;
        this.#method();
    }
}

Changes

• Include PrivateIdentifier nodes in the existing symbol-classification path.
• Classify private fields as property and private methods as method.
• Apply the declaration modifier to private member declarations.
• Add regression coverage for declarations and references.

• Fixes [Bug] PrivateIdentifier nodes are omitted from 2020 semantic classifications #64322