Update doc/command_line_usage.rdoc

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: hsbt

doc/command_line_usage.rdoc

@@ -105,8 +105,7 @@ Options are:
     Require _name_ before executing the Rakefile.
 
 [<tt>--rules</tt>]
-    Trace the rules resolution, including how implicit file tasks are
-    being synthesized.
+    Trace the resolution of rules used to create tasks.
 
 [<tt>--silent (-s)</tt>]
     Like --quiet, but also suppresses the 'in directory' announcement.