Update documentation according to changes in MWBS

doc/user/project/merge_requests/merge_when_build_succeeds.md

 # Merge When Build Succeeds
 
 When reviewing a merge request that looks ready to merge but still has one or
-more CI builds running, you can set it to be merged automatically when all
-builds succeed. This way, you don't have to wait for the builds to finish and
-remember to merge the request manually.
+more CI builds running, you can set it to be merged automatically when the
+builds pipeline succeed. This way, you don't have to wait for the builds to
+finish and remember to merge the request manually.
 
 ![Enable](img/merge_when_build_succeeds_enable.png)
 
 When you hit the "Merge When Build Succeeds" button, the status of the merge
 request will be updated to represent the impending merge. If you cannot wait
-for the build to succeed and want to merge immediately, this option is available
-in the dropdown menu on the right of the main button.
+for the pipeline to succeed and want to merge immediately, this option is
+available in the dropdown menu on the right of the main button.
 
 Both team developers and the author of the merge request have the option to
 cancel the automatic merge if they find a reason why it shouldn't be merged
@@ -18,9 +18,9 @@ after all.
 
 ![Status](img/merge_when_build_succeeds_status.png)
 
-When the build succeeds, the merge request will automatically be merged. When
-the build fails, the author gets a chance to retry any failed builds, or to
-push new commits to fix the failure.
+When the pipeline succeeds, the merge request will automatically be merged.
+When the pipeline fails, the author gets a chance to retry any failed builds,
+or to push new commits to fix the failure.
 
 When the builds are retried and succeed on the second try, the merge request
 will automatically be merged after all. When the merge request is updated with
@@ -40,7 +40,7 @@ hit **Save** for the changes to take effect.
 
 ![Only allow merge if build succeeds settings](img/merge_when_build_succeeds_only_if_succeeds_settings.png)
 
-From now on, every time the build fails you will not be able to merge the merge
-request from the UI, until you make the build pass.
+From now on, every time the pipelinefails you will not be able to merge the
+merge request from the UI, until you make all relevant builds pass.
 
 ![Only allow merge if build succeeds msg](img/merge_when_build_succeeds_only_if_succeeds_msg.png)