Add link to documentation in push check when a secret is detected

Overview

As a way to help users understand more about the feature and also to know what to do when a secret is detected, we should consider adding a link to the documentation page added in !139496 (merged).

Original Discussion

The following discussion from !139496 (merged) should be addressed:

• @serenafang started a discussion: (+3 comments)

  Thanks @ahmed.hemdan! As a follow up, after this merges in, it'd be super great to link to it in the Git error response, like:

  Gitlab: Secret detection scan completed with one or more findings: 
  
  Secret leaked in commit: 123abc
  filename:5 | Gitlab PAT
  
  Please remove the secrets, update your commits, and try again.
  
  For help with this, please refer to our documentation: 
  https://docs.gitlab.com/ee/user/application_security/secret_detection/pre_receive.html

  (or something)

  I opened an issue to track this idea: #435093 (closed)

Implementation Plan

• Update secrets push check to include a link to the documentation when a secret is detected.

Proposal

The proposal for the text used is below.

For help with this, please refer to our documentation: https://docs.gitlab.com/ee/user/application_security/secret_detection/pre_receive.html