feat(support): add params hash with indifferent access

lib/prism/params.rb

@@ -0,0 +1,36 @@
+module Prism
+  class Params < Hash
+    def self.from(source)
+      source.each_with_object(new) { |(key, value), acc| acc[key] = value }
+    end
+
+    def [](key)
+      super(convert_key(key))
+    end
+
+    def []=(key, value)
+      super(convert_key(key), value)
+    end
+
+    def fetch(key, *rest, &block)
+      super(convert_key(key), *rest, &block)
+    end
+
+    def dig(key, *rest)
+      super(convert_key(key), *rest)
+    end
+
+    def key?(key)
+      super(convert_key(key))
+    end
+    alias_method :has_key?, :key?
+    alias_method :include?, :key?
+    alias_method :member?, :key?
+
+    private
+
+    def convert_key(key)
+      key.is_a?(Symbol) ? key.to_s : key
+    end
+  end
+end