Support Ruby 3.4's it keyword

[amomchilov]

... once upstream Sorbet starts supporting it. sorbet#8375

#228 configured Prism to parse in Ruby 3.3 mode:

sorbet/parser/prism/Parser.h

Lines 19 to 20 in 082c0c9

	// The version of Ruby syntax that we're parsing with Prism. This determines what syntax is supported or not.
	static constexpr std::string_view ParsedRubyVersion = "3.3.0";

We'll need to update that to 3.4 (reference), then update the translation layer to match Sorbet.