Use clearer class name in HTTP client

We create our own special HTTP request subclass in order to send a GET
request without reading the body but the class name misleadingly says it
is without response (which isn't true).

Rename the class to GetWithoutBody which hopefully makes this a little
clearer.

lib/embiggen/http_client.rb

@@ -2,7 +2,7 @@
 require 'net/http'
 
 module Embiggen
-  class GetWithoutResponse < ::Net::HTTPRequest
+  class GetWithoutBody < ::Net::HTTPRequest
     METHOD = 'GET'.freeze
     REQUEST_HAS_BODY = false
     RESPONSE_HAS_BODY = false
@@ -30,7 +30,7 @@ def follow(timeout)
     private
 
     def request(timeout)
-      request = GetWithoutResponse.new(uri.request_uri)
+      request = GetWithoutBody.new(uri.request_uri)
       http.open_timeout = timeout
       http.read_timeout = timeout