Fix CRUD pages for tempmon clients, probes

for some reason if helptext had embedded newlines, it would now fail
to render the form altogether.  guess that is a result of recent
change to e.g. `<b-field :message="['foo', 'bar']">` logic,
somehow.. anyway hopefully this fixes and no more surprises

tailbone/forms/core.py

@@ -755,7 +755,8 @@ class Form(object):
         """
         Set the help text for a given field.
         """
-        self.helptext[key] = value
+        # nb. must avoid newlines, they cause some weird "blank page" error?!
+        self.helptext[key] = value.replace('\n', ' ')
         if value and dynamic:
             self.dynamic_helptext[key] = True
         else:
@@ -1009,6 +1010,8 @@ class Form(object):
             # render the field widget or whatever
             if self.readonly or fieldname in self.readonly_fields:
                 html = self.render_field_value(fieldname) or HTML.tag('span')
+                if type(html) is str:
+                    html = HTML.tag('span', c=[html])
             elif field:
                 html = field.serialize(**self.get_renderer_kwargs(fieldname))
                 html = HTML.literal(html)