The macro provided by symbol.h uses STATIC_ID2SYM
when it can which speeds up methods that declare keyword args.

Co-authored-by: Alan Wu <XrXr@users.noreply.github.com>
Co-authored-by: Takashi Kokubun (k0kubun) <takashikkbn@gmail.com>
Co-authored-by: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>