simulation: don't put divergence description between ()

Using an em html tag is enough to have to display the explanation
message differently, not need to wrap it in paranthesis, which does not
look so good in some languages.

bt5/erp5_simulation/SkinTemplateItem/portal_skins/erp5_simulation/SolverDecision_getDivergenceDescription.py

@@ -3,6 +3,6 @@ from Products.PythonScripts.standard import html_quote
 # even if we have several divergence testers, the first
 # one is enough for displaying the title.
 tester = context.getCausalityValue()
-return '<div>%s</div><div><em>(%s)</em></div>' % (
+return '<div>%s</div><div><em>%s</em></div>' % (
     html_quote(tester.getTranslatedTitle()),
     context.getExplanationMessage())