Docs: improve id-match usage advice (#9544)

docs/rules/id-match.md

@@ -83,4 +83,4 @@ do_something(__dirname);
 
 ## When Not To Use It
 
-If your rules are too complex, it is possible that you encounter performance issues due to the nature of the job.
+If you don't want to enforce any particular naming convention for all identifiers, or your naming convention is too complex to be enforced by configuring this rule, then you should not enable this rule.