[Tagging] phone validity - phone "preset"

[marc marc]

Hello,

on the french-speaking mailing, a contributor noticed a high rate
of incorrect value for the tag "phone". the most common error is using 
the national format number instead of the international format.

A monthly project 'll maybe fix some of those errors.
Some quality tool can help those fix.

But the best would be to avoid the mistake when a user fill
in the data in iD, josm or whatever.

Is anyone aware of a kind of "preset" that can be used for phone ?
Otherwise it would be useful to create with local communities a wiki 
page containing a list of valid prefixes example + 322xxxxxxx is valid, 
+331xxxxxxxx also but 01xxxxxxxx is not valid in France.
Or using something like https://github.com/googlei18n/libphonenumber/
https://github.com/googlei18n/libphonenumber/blob/master/FAQ.md#where-do-we-get-information-from-to-determine-if-a-number-range-is-valid

Would it also be useful to put a corrective suggestion?
for example 01xxxxxxxx #+331xxxxxxxx

Of course, I am not talking about the exact form of the list,
nor the fact that some countries will have a list,
while others not.
nor the difficulty when a poi has several corresponding numbers
attached several countries.
I 'm talking about the general guideline.

The aim is not to forbid some values but to allow
common editor to guide the user to avoid a very common error.