Add crosslink to variables examples

doc/ci/merge_request_pipelines/index.md

@@ -146,7 +146,7 @@ test:
 
 Instead, you can use the
 [`$CI_COMMIT_REF_NAME` predefined environment
-variable](../variables/predefined_variables.md#variables-reference) in
+variable](../variables/predefined_variables.md) in
 combination with
 [`only:variables`](../yaml/README.md#onlyvariablesexceptvariables) to
 accomplish this behavior:

doc/ci/triggers/README.md

@@ -23,7 +23,7 @@ The following methods of authentication are supported:
 - [Trigger token](#trigger-token)
 - [CI job token](#ci-job-token)
 
-If using the `$CI_PIPELINE_SOURCE` [predefined environment variable](../variables/predefined_variables.md#variables-reference)
+If using the `$CI_PIPELINE_SOURCE` [predefined environment variable](../variables/predefined_variables.md)
 to limit which jobs run in a pipeline, the value could be either `pipeline` or `trigger`,
 depending on which trigger method is used.
 

doc/ci/variables/predefined_variables.md

@@ -10,8 +10,6 @@ type: reference
 For an introduction on this subject, read through the
 [getting started with environment variables](README.md) document.
 
-## Overview
-
 Some of the predefined environment variables are available only if a minimum
 version of [GitLab Runner](https://docs.gitlab.com/runner/) is used. Consult the table below to find the
 version of Runner required.
@@ -22,7 +20,8 @@ Starting with GitLab 9.0, we have deprecated some variables. Read the
 strongly advised to use the new variables as we will remove the old ones in
 future GitLab releases.**
 
-## Variables reference
+You can add a command to your `.gitlab-ci.yml` file to
+[output the values of all variables available for a job](README.md#list-all-environment-variables).
 
 | Variable                                      | GitLab | Runner | Description                                                                                                                                                                                                                                                                                                                                                |
 |-----------------------------------------------|--------|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

doc/ci/yaml/README.md

@@ -1428,7 +1428,7 @@ This means the `only:changes` policy is useful for pipelines where:
 - `$CI_PIPELINE_SOURCE == 'external_pull_request_event'`
 
 If there is no Git push event, such as for pipelines with
-[sources other than the three above](../variables/predefined_variables.md#variables-reference),
+[sources other than the three above](../variables/predefined_variables.md),
 `changes` can't determine if a given file is new or old, and will always
 return true.
 

doc/development/integrations/secure.md

@@ -91,7 +91,7 @@ disable running the custom scanner.
 GitLab also defines a `CI_PROJECT_REPOSITORY_LANGUAGES` variable, which provides the list of
 languages in the repository. Depending on this value, your scanner may or may not do something different.
 Language detection currently relies on the [`linguist`](https://github.com/github/linguist) Ruby gem.
-See [GitLab CI/CD predefined variables](../../ci/variables/predefined_variables.md#variables-reference).
+See [GitLab CI/CD predefined variables](../../ci/variables/predefined_variables.md).
 
 #### Policy checking example