Fix some SimpleMDE (#9400)

Signed-off-by: jolheiser <john.olheiser@gmail.com>

routers/repo/pull.go

@@ -588,6 +588,7 @@ func ViewPullFiles(ctx *context.Context) {
 	setPathsCompareContext(ctx, baseCommit, commit, headTarget)
 
 	ctx.Data["RequireHighlightJS"] = true
+	ctx.Data["RequireSimpleMDE"] = true
 	ctx.Data["RequireTribute"] = true
 	if ctx.Data["Assignees"], err = ctx.Repo.Repository.GetAssignees(); err != nil {
 		ctx.ServerError("GetAssignees", err)