Update all only: and except: to take arrays

This commit updates all instances in the documentation where we
reference only: or except: to ensure they show the setting accepting an
array (as opposed to a single value).

Only/except do not support single values (i.e. `only: merge_requests`
is invalid).

doc/ci/jenkins/index.md

@@ -228,5 +228,5 @@ our very powerful [`only/except` rules system](../yaml/README.md#onlyexcept-basi
 
 ```yaml
 my_job:
-  only: branches
+  only: [branches]
 ```

doc/ci/merge_request_pipelines/index.md

@@ -30,7 +30,7 @@ Pipelines for merge requests have the following requirements and limitations:
 
 ## Configuring pipelines for merge requests
 
-To configure pipelines for merge requests, add the `only: merge_requests` parameter to
+To configure pipelines for merge requests, add the `only: [merge_requests]` parameter to
 the jobs that you want to run only for merge requests.
 
 Then, when developers create or update merge requests, a pipeline runs
@@ -68,7 +68,7 @@ After the merge request is updated with new commits:
 - The pipeline fetches the latest code from the source branch and run tests against it.
 
 In the above example, the pipeline contains only a `test` job.
-Since the `build` and `deploy` jobs don't have the `only: merge_requests` parameter,
+Since the `build` and `deploy` jobs don't have the `only: [merge_requests]` parameter,
 they will not run in the merge request.
 
 Pipelines tagged with the **detached** badge indicate that they were triggered
@@ -86,7 +86,7 @@ Read the [documentation on Merge Trains](pipelines_for_merged_results/merge_trai
 
 ## Excluding certain jobs
 
-The behavior of the `only: merge_requests` parameter is such that _only_ jobs with
+The behavior of the `only: [merge_requests]` parameter is such that _only_ jobs with
 that parameter are run in the context of a merge request; no other jobs will be run.
 
 However, you may want to reverse this behavior, having all of your jobs to run _except_

doc/ci/yaml/README.md

@@ -780,7 +780,7 @@ it is possible to define a job to be created based on files modified
 in a merge request.
 
 In order to deduce the correct base SHA of the source branch, we recommend combining
-this keyword with `only: merge_requests`. This way, file differences are correctly
+this keyword with `only: [merge_requests]`. This way, file differences are correctly
 calculated from any further commits, thus all changes in the merge requests are properly
 tested in pipelines.
 
@@ -802,7 +802,7 @@ either files in `service-one` directory or the `Dockerfile`, GitLab creates
 and triggers the `docker build service one` job.
 
 Note that if [pipelines for merge requests](../merge_request_pipelines/index.md) is
-combined with `only: change`, but `only: merge_requests` is omitted, there could be
+combined with `only: [change]`, but `only: [merge_requests]` is omitted, there could be
 unwanted behavior.
 
 For example:

doc/development/documentation/styleguide.md

@@ -699,7 +699,7 @@ nicely on different mobile devices.
 ## Code blocks
 
 - Always wrap code added to a sentence in inline code blocks (`` ` ``).
-  E.g., `.gitlab-ci.yml`, `git add .`, `CODEOWNERS`, `only: master`.
+  E.g., `.gitlab-ci.yml`, `git add .`, `CODEOWNERS`, `only: [master]`.
   File names, commands, entries, and anything that refers to code should be added to code blocks.
   To make things easier for the user, always add a full code block for things that can be
   useful to copy and paste, as they can easily do it with the button on code blocks.

doc/user/project/merge_requests/merge_when_pipeline_succeeds.md

@@ -69,7 +69,7 @@ For example, to that on merge requests there is always a passing job even though
 
 ```yaml
 enable_merge:
-  only: merge_requests
+  only: [merge_requests]
   script:
     - echo true
 ```