Insert fake todo entry for a conflicting commit that is being applied

When stopping in a rebase because of a conflict, it is nice to see the commit
that git is trying to apply. Create a fake todo entry labelled "conflict" for
this, and show the "<-- YOU ARE HERE ---" string for that one (in red) instead
of for the real current head.

pkg/integration/tests/sync/pull_rebase_interactive_conflict.go

@@ -47,7 +47,8 @@ var PullRebaseInteractiveConflict = NewIntegrationTest(NewIntegrationTestArgs{
 		t.Views().Commits().
 			Lines(
 				Contains("pick").Contains("five"),
-				Contains("YOU ARE HERE").Contains("three"),
+				Contains("conflict").Contains("YOU ARE HERE").Contains("four"),
+				Contains("three"),
 				Contains("two"),
 				Contains("one"),
 			)