[ruby/rubygems] Fix wrong expected value in Rust extension test templates

The Rust function hello("world") returns "Hello world, from Rust!" but
the Ruby test templates expected "Hello earth, from Rust!", causing
generated tests to fail immediately after bundle gem --ext=rust.

ruby/rubygems@8de4c041ba

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

lib/bundler/templates/newgem/spec/newgem_spec.rb.tt

@@ -9,7 +9,7 @@ RSpec.describe <%= config[:constant_name] %> do
   it "can call into Rust" do
     result = <%= config[:constant_name] %>.hello("world")
 
-    expect(result).to be("Hello earth, from Rust!")
+    expect(result).to be("Hello world, from Rust!")
   end
 <%- else -%>
   it "does something useful" do

lib/bundler/templates/newgem/test/minitest/test_newgem.rb.tt

@@ -9,7 +9,7 @@ class <%= config[:minitest_constant_name] %> < Minitest::Test
 
 <%- if config[:ext] == 'rust' -%>
   def test_hello_world
-    assert_equal "Hello earth, from Rust!", <%= config[:constant_name] %>.hello("world")
+    assert_equal "Hello world, from Rust!", <%= config[:constant_name] %>.hello("world")
   end
 <%- else -%>
   def test_it_does_something_useful