[webui] Convert ERB partial to HAML

src/api/app/views/webui/request/_superseded_by_message.html.haml

@@ -0,0 +1,30 @@
+- if superseding.present? && superseded_by.nil? && diff_to_superseded.nil?
+  .grid_16.alpha.omega.box-invisible
+    .ui-state-info.ui-corner-all.ui-widget-shadow.padding-10pt#request-supersedes-hint
+      %span.ui-icon.ui-icon-info
+        This request supersedes:
+        - superseding.each do |bs_request|
+          = link_to "request #{bs_request.number}", request_show_path(number: bs_request.number)
+          (
+          = link_to 'Show diff', request_show_path(number: bs_request.superseded_by, diff_to_superseded: bs_request.number)
+          )
+- if superseded_by.present?
+  .grid_16.alpha.omega.box-invisible
+    .ui-state-info.ui-corner-all.ui-widget-shadow.padding-10pt#request-superseded-by-hint
+      %span.ui-icon.ui-icon-info
+        This request is superseded by
+        = link_to "request #{superseded_by}", request_show_path(number: superseded_by)
+        (
+        = link_to 'Show diff', request_show_path(number: superseded_by, diff_to_superseded: number)
+        )
+- if diff_to_superseded.present?
+  .grid_16.alpha.omega.box-invisible
+    .ui-state-info.ui-corner-all.ui-widget-shadow.padding-10pt#truncated-diff-hint
+      %span.ui-icon.ui-icon-info
+        You're not reviewing the full diff of
+        = link_to "request #{number}", request_show_path(number: number)
+        but the diff to the superseded
+        = link_to "request #{diff_to_superseded.number}", request_show_path(number: diff_to_superseded)
+        (
+        = link_to 'Show full diff', request_show_path(number: number)
+        )