Wikipedia should be able to know whether an article exists on the Wiktionary or
on Commons and point to it accordingly.

Currently if the user goes to http://fr.wikipedia.org/wiki/Miaou
A message like "Look for Miaou in Wiktionary, our sister dictionary project" and
a similar one for commons.

The user shouldn't have to look around, but should know right away if an article
actually exists on the Wiktionnary or on Commons.
The feature should also be able to point to articles with or without the initial
letter in uppercase, since some wiktionaries are case sensitive and some aren't
Miaou on Wikipedia could point to Miaou or miaou on the Wiktionary; either/both
should be valid and presented as an option to the user.

Version: unspecified
Severity: enhancement