docs(guide): correct broken URL for helpers module (#3289)

Author: yoshi2no

docs/guide/index.md

@@ -43,7 +43,7 @@ Faker has three types of modules:
 
 - Modules for basic datatypes: [`datatype`](/api/datatype), [`date`](/api/date), [`number`](/api/number) and [`string`](/api/string)
 - Topic specific modules, such as [`animal`](/api/animal), [`food`](/api/food) and many more
-- Lastly, the [`helpers`](/api/datatype) module, with various utility methods to use with your own data (or data generated by other Faker methods)
+- Lastly, the [`helpers`](/api/helpers) module, with various utility methods to use with your own data (or data generated by other Faker methods)
 
 For a full list of modules, go to our [Api Search](/api/) page.