Make MR link in build sidebar bold

It adds some consistency compared to the links in the header, which
are also bold.

app/views/projects/builds/_sidebar.html.haml

@@ -48,7 +48,8 @@
       - if @build.merge_request
         %p.build-detail-row
           %span.build-light-text Merge Request:
-          = link_to "#{@build.merge_request.to_reference}", merge_request_path(@build.merge_request)
+          = link_to merge_request_path(@build.merge_request) do
+            %strong= "#{@build.merge_request.to_reference}"
       - if @build.duration
         %p.build-detail-row
           %span.build-light-text Duration:

changelogs/unreleased/tc-job-page-mr-bold.yml

@@ -0,0 +1,4 @@
+---
+title: Make MR link in build sidebar bold
+merge_request:
+author: