Clean up font-lock rules in js-ts-mode

Clean up font-lock rules in js-ts-mode

Changes for each feature:

- string: Take out string-interpolation bits.
- string-interpolation: New.
- declaration: Rename to definition.
- identifier: Remove.
- property: Use a pred to filter out methods.
- expression: Rename to assignment.
- function: New.
- pattern: Merge into assignment.

* lisp/progmodes/js.el (js--treesit-font-lock-settings): See above.
(js--treesit-property-not-function-p)
(js--treesit-lhs-identifier-query): New variable.
(js--treesit-fontify-assignment-lhs): New functions.
(js-ts-mode): Update feature list.