Fix UnnecessaryStringOutput HAML linter

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/views/groups/pipeline_quota/index.html.haml

@@ -22,7 +22,7 @@
         minutes
     .col-sm-6.right
       - if @group.shared_runners_minutes_limit_enabled?
-        = "#{group_shared_runner_limits_percent_used(@group)}% used"
+        #{group_shared_runner_limits_percent_used(@group)}% used
       - else
         Unlimited
       = group_shared_runner_limits_progress_bar(@group)

app/views/notify/approved_merge_request_email.text.haml

-= "Merge Request #{@merge_request.to_reference} was approved by #{@approved_by_user}"
+Merge Request #{@merge_request.to_reference} was approved by #{@approved_by_user}
 
 Merge Request url: #{namespace_project_merge_request_url(@merge_request.target_project.namespace, @merge_request.target_project, @merge_request)}
 

app/views/notify/unapproved_merge_request_email.text.haml

-= "Merge Request #{@merge_request.to_reference} was unapproved by #{@unapproved_by_user}"
+Merge Request #{@merge_request.to_reference} was unapproved by #{@unapproved_by_user}
 
 Merge Request url: #{namespace_project_merge_request_url(@merge_request.target_project.namespace, @merge_request.target_project, @merge_request)}