Remove unintended new line in gem query deprecation message

With it, the warning looks weird, like this:

```
WARNING:  query command is deprecated. It will be removed in Rubygems 4.
WARNING:
It is recommended that you use `gem search` or `gem list` instead.
```

Author: deivid-rodriguez

lib/rubygems/commands/query_command.rb

@@ -13,7 +13,7 @@ class Gem::Commands::QueryCommand < Gem::Command
   def deprecation_warning
     warning_without_suggested_alternatives
 
-    message = "\nIt is recommended that you use `gem search` or `gem list` instead.\n"
+    message = "It is recommended that you use `gem search` or `gem list` instead.\n"
     alert_warning message unless Gem::Deprecate.skip
   end
 

test/rubygems/test_gem_gem_runner.rb

@@ -78,7 +78,7 @@ def test_query_is_deprecated
     end
 
     assert_match(/WARNING:  query command is deprecated. It will be removed in Rubygems [0-9]+/, @ui.error)
-    assert_match(/It is recommended that you use `gem search` or `gem list` instead/, @ui.error)
+    assert_match(/WARNING:  It is recommended that you use `gem search` or `gem list` instead/, @ui.error)
   end
 
   def test_info_succeeds