Tweak docs:generate warning

lib/tasks/docs.thor

@@ -62,23 +62,25 @@ class DocsCLI < Thor
     Docs.install_report :scraper if options[:debug]
     Docs.install_report :progress_bar, :doc if $stdout.tty?
 
-    unless options[:force]
+    require 'unix_utils' if options[:package]
+
+    doc = Docs.find(name, options[:version])
+
+    if doc < Docs::UrlScraper && !options[:force]
       puts <<-TEXT.strip_heredoc
-        Note: this command will scrape the documentation from the source.
-        Some scrapers require a local setup. Others will send thousands of
-        HTTP requests, potentially slowing down the source site.
-        Please don't use it unless you are modifying the code.
+        /!\\ WARNING /!\\
+
+        Some scrapers send thousands of HTTP requests in a short period of time,
+        which can slow down the source site and trouble its maintainers.
 
-        To download the latest tested version of a documentation, use:
+        Please scrape responsibly. Don't do it unless you're modifying the code.
+
+        To download the latest tested version of this documentation, run:
           thor docs:download #{name}\n
       TEXT
       return unless yes? 'Proceed? (y/n)'
     end
 
-    require 'unix_utils' if options[:package]
-
-    doc = Docs.find(name, options[:version])
-
     result = if doc.version && options[:all]
       doc.superclass.versions.all? do |_doc|
         puts "==> #{_doc.version}"