Fix a typo

Author: gotjosh

README.md

@@ -62,7 +62,7 @@ This command will load each rule group in the specified files and load them into
 
 #### Rules Lint
 
-This command lints a rules file. The linter's aim is not verify correctness but just YAML and PromQL expression formatting within the rule file. This command always edits in place, you can use the dry run flag (`-n`) if you'd like to perform a trial run that does not make any changes.
+This command lints a rules file. The linter's aim is not to verify correctness but just YAML and PromQL expression formatting within the rule file. This command always edits in place, you can use the dry run flag (`-n`) if you'd like to perform a trial run that does not make any changes.
 
     cortextool rules lint -n ./example_rules_one.yaml ./example_rules_two.yaml ...