fix(locale): Dutch phone number

[RobinvanderVliet]

A Dutch phone number in national format consists of 10 digits. For mobile numbers, the second digit is always six. To obtain the international format, substitute the leading zero with "+31".

This pull request guarantees adherence to this format for all phone numbers and also includes examples of the international format.

[codecov]

Codecov Report

Merging #2400 (7ae18cd) into next (da423b6) will increase coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             next    #2400      +/-   ##
==========================================
+ Coverage   99.59%   99.61%   +0.01%     
==========================================
  Files        2801     2801              
  Lines      252469   252476       +7     
  Branches     1095     1104       +9     
==========================================
+ Hits       251458   251497      +39     
+ Misses        984      952      -32     
  Partials       27       27              

Files Changed	Coverage Δ
src/locales/nl/phone_number/formats.ts	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes