strategy#page_content: align comments to future intentions

@samford is working on the ability to specify custom UA (among other things)
in livecheck blocks; "retrying" will cease to be relevant

Co-authored-by: Sam Ford <1584702+samford@users.noreply.github.com>

Library/Homebrew/livecheck/strategy.rb

@@ -58,8 +58,8 @@ module Homebrew
       # `curl` arguments used in `Strategy#page_content` method.
       PAGE_CONTENT_CURL_ARGS = ([
         "--compressed",
-        # Allow the return of an error code on exit, so that we can retry
-        # with a fake UA string (e.g. for Cloudflare-protected sites)
+        # Return an error when the HTTP response code is 400 or greater but
+        # continue to return body content
         "--fail-with-body",
         # Include HTTP response headers in output, so we can identify the
         # final URL after any redirections