Change `start_at` label to Start time

Humanize a start_at label in Prometheus::AlertPresenter

ee/app/presenters/projects/prometheus/alert_presenter.rb

@@ -58,7 +58,7 @@ module Projects
       def metadata_list
         metadata = []
 
-        metadata << list_item('starts_at', starts_at) if starts_at
+        metadata << list_item('Start time', starts_at) if starts_at
         metadata << list_item('full_query', backtick(full_query)) if full_query
 
         metadata.join(MARKDOWN_LINE_BREAK)

ee/spec/presenters/projects/prometheus/alert_presenter_spec.rb

@@ -45,7 +45,7 @@ describe Projects::Prometheus::AlertPresenter do
           <<~MARKDOWN.chomp
             #### Summary
 
-            **starts_at:** #{presenter.starts_at}
+            **Start time:** #{presenter.starts_at}
 
           MARKDOWN
         )
@@ -62,7 +62,7 @@ describe Projects::Prometheus::AlertPresenter do
           <<~MARKDOWN.chomp
             #### Summary
 
-            **starts_at:** #{presenter.starts_at}
+            **Start time:** #{presenter.starts_at}
 
             #### Alert Details
 
@@ -82,7 +82,7 @@ describe Projects::Prometheus::AlertPresenter do
           <<~MARKDOWN.chomp
             #### Summary
 
-            **starts_at:** #{presenter.starts_at}  \n**full_query:** `query`
+            **Start time:** #{presenter.starts_at}  \n**full_query:** `query`
 
           MARKDOWN
         )