Fix error with prism when method given no arguments

such as:

  p = Proc.new

This now matches the RubyVM::AbstractSyntaxTree behavior, which is
not to highlight anything.

Author: luke-gru

lib/error_highlight/base.rb

@@ -700,6 +700,9 @@ def prism_spot_call_for_name
     #   foo 42
     #       ^^
     def prism_spot_call_for_args
+      # Disallow highlighting arguments if there are no arguments.
+      return if @node.arguments.nil?
+
       # Explicitly turn off foo.() syntax because error_highlight expects this
       # to not work.
       return nil if @node.name == :call && @node.message_loc.nil?

test/test_error_highlight.rb

@@ -197,6 +197,15 @@ def test_CALL_arg_6
     end
   end
 
+  def test_CALL_arg_7
+    assert_error_message(ArgumentError, <<~END) do
+tried to create Proc object without a block (ArgumentError)
+    END
+
+      Proc.new
+    end
+  end
+
   def test_QCALL_1
     assert_error_message(NoMethodError, <<~END) do
 undefined method `foo' for #{ ONE_RECV_MESSAGE }