* lisp/progmodes/ruby-ts-mode.el (ruby-ts--font-lock-settings):
Use font-lock-string-face for %w() and `...`.
Use font-lock-constant-face (just like we do for symbol literals)
for symbol array literals, %i().
Combine the matchers for string content and heredocs.
* etc/NEWS: Mention the new mode.
* lisp/progmodes/ruby-ts-mode.el: New file.
* test/lisp/progmodes/ruby-ts-mode-tests.el: New file.
* lisp/progmodes/eglot.el (eglot-server-programs):
Add ruby-ts-mode to the Ruby entry.
Co-authored-by: Dmitry Gutov <dgutov@yandex.ru>