Merge branch 'patch-5' into 'master'

Update pipelines.md

## What does this MR do?

attempt to solve:
https://gitlab.com/gitlab-org/gitlab-ce/commit/a03cadcdbf3024ec59234a07a9b87884de5cc7dc#note_14172234

the word isn't visible anyway, don't know what original author intended to say. at least it fixes the `stages` link now.

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)

See merge request !6040

doc/ci/pipelines.md

@@ -5,7 +5,7 @@ Introduced in GitLab 8.8.
 
 ## Pipelines
 
-A pipeline is a group of [builds] that get executed in [stages] (batches). All
+A pipeline is a group of [builds] that get executed in [stages] \(batches). All
 of the builds in a stage are executed in parallel (if there are enough
 concurrent [runners]), and if they all succeed, the pipeline moves on to the
 next stage. If one of the builds fails, the next stage is not (usually)