Update README.md

fix doc

Co-authored-by: nodivbyzero <[email protected]>

Author: peczenyj

README.md

@@ -262,7 +262,7 @@ validate := validator.New(validator.WithRequiredStructEnabled())
 | excluded_without | Excluded Without |
 | excluded_without_all | Excluded Without All |
 | unique | Unique |
-| isvalid | Verify if the method `Validate() error` does not return an error |
+| validateFn | Verify if the method `Validate() error` does not return an error |
 
 
 #### Aliases: