Add support for Ruby 3.1's Hash punning.

Author: nirvdrum

CHANGELOG.md

@@ -4,6 +4,7 @@ New features:
 
 * Foreign strings now have all methods of Ruby `String`. They are treated as `#frozen?` UTF-8 Ruby Strings.
 * Add `Java.add_to_classpath` method to add jar paths at runtime (#2693, @bjfish).
+* Add support for Ruby 3.1's Hash shorthand/punning syntax (@nirvdrum).
 
 Bug fixes:
 

spec/tags/language/hash_tags.txt

@@ -1,2 +1,3 @@
 fails:The ** operator makes a caller-side copy when calling a method taking a positional Hash
 fails:Hash literal checks duplicated keys on initialization
+fails:Hash literal checks duplicated float keys on initialization

spec/truffleruby.mspec

@@ -103,6 +103,7 @@ class MSpecScript
 
   # Use spec/ruby/core/nil/nil_spec.rb as a dummy file to avoid being empty
   set :next, %w[
+    spec/ruby/language/hash_spec.rb
     spec/ruby/core/nil/nil_spec.rb
     spec/ruby/core/gc/measure_total_time_spec.rb
     spec/ruby/core/gc/total_time_spec.rb