Change to TagFix_Housenumber.py as per discussion in PR

Adjusting the wording of the sentence as per the discussion with @Famlam.

plugins/TagFix_Housenumber.py

@@ -41,7 +41,7 @@ def init(self, logger):
             title = T_('Invalid addr:interpolation or addr:inclusion value'),
             detail = T_(
 '''* Tag `addr:interpolation=*` is only valid with values: `even`, `odd`,
-`all`, `alphabetic` and `Number`.
+`all`, `alphabetic` or a number.
 * Tag `addr:inclusion=*` is only valid with values: `actual`, `estimate`
 and `potential`.'''))